v. Cooper

The summaries of the Colorado Court of Appeals published opinions
constitute no part of the opinion of the division but have been prepared by
the division for the convenience of the reader. The summaries may not be
cited or relied upon as they are not the official language of the division.
Any discrepancy between the language in the summary and in the opinion
should be resolved in favor of the language in the opinion.

SUMMARY
February 21, 2019

2019COA21

No. 15CA0576, People v. Cooper — Evidence — Relevancy and
Its Limits — Irrelevant Evidence Inadmissible — Testimony by
Experts

In this criminal appeal, the division holds that the existence of

an intimate relationship does not, by itself and without evidence of

escalating abuse or violence, justify the admission of blind expert

testimony on the cycle of violence or other attributes of an abusive

relationship. The majority concludes the admission of such

evidence in this case, where there was no evidence presented that

the defendant and victim had a history of domestic abuse or

violence, was not harmless and reverses the defendant’s conviction

and remands for a new trial.

The partial dissent agrees that allowing the testimony of the

domestic violence blind expert was an abuse of discretion because it
was irrelevant in this case. Nonetheless, based on this record, the

partial dissent would conclude that the expert’s testimony was

harmless and affirm the jury’s verdict.
COLORADO COURT OF APPEALS 2019COA21

Court of Appeals No. 15CA0576
El Paso County District Court No. 13CR2453
Honorable Michael P. McHenry, Judge

The People of the State of Colorado,

Plaintiff-Appellee,

v.

Kerry Lee Cooper,

Defendant-Appellant.

JUDGMENT REVERSED AND CASE
REMANDED WITH DIRECTIONS

Division V
Opinion by JUDGE BERGER
Richman, J., concurs
Román, J., concurs in part and dissents in part

Announced February 21, 2019

Philip J. Weiser, Attorney General, Charlotte M. Powers, Assistant Attorney
General, Denver, Colorado, for Plaintiff-Appellee

Megan A. Ring, Colorado State Public Defender, Tracy C. Renner, Deputy State
Public Defender, Denver, Colorado, for Defendant-Appellant
I. Introduction and Summary

¶1 The principal issue in this appeal of a criminal prosecution for

menacing, assault, harassment, and cruelty to an animal, is the

propriety of the admission of “blind” expert testimony regarding the

dynamics of abusive intimate relationships.

¶2 A “blind” or “cold” expert knows little or nothing about the

facts of a particular case, often has not met the victim, and has not

performed any forensic or psychological examination of the victim

(or the defendant). See Fed. R. Evid. 702 advisory committee’s note

to 2000 amendments; see also Christopher Tarver Robertson, Blind

Expertise, 85 N.Y.U. L. Rev. 174 (2010). 1

¶3 Colorado courts repeatedly have recognized the value of blind

expert testimony in appropriate cases. Venalonzo v. People, 2017

CO 9, ¶¶ 32-34; People v. Wittrein, 221 P.3d 1076, 1081 (Colo.

2009); People v. Relaford, 2016 COA 99, ¶¶ 26-30; see also People v.

Fortson, 2018 COA 46M (Berger, J., specially concurring). When

1 Sometimes, blind experts are referred to as “general,” as opposed

to “case-specific,” experts. Victoria L. Lutz, A Guide to Domestic
Violence Expert Testimony in Colorado, 45 Colo. Law. 63 (Nov. 2016)
as reprinted in The Journal of American Judges Association, 53
Court Review 22, available at https://perma.cc/QSH6-UJL5.

1
the actions of a victim are counterintuitive to what an ordinary

juror might expect, this type of expert testimony may be crucial in

explaining to the jury what social science has learned about the

behavior patterns of people who are involved in violent

relationships. Venalonzo, ¶¶ 32-34. Without this testimony, jurors

may well reach incorrect decisions because they do not have the

background to understand such counterintuitive actions. Relaford,

¶ 30. Nothing in this opinion questions the admissibility of such

testimony in the proper case. 2

¶4 But, there are substantial risks attendant to the admission of

blind expert testimony that cannot be ignored. When blind expert

testimony is used to persuade the jury to make findings of historical

fact that are not supported by evidence presented to the jury, the

trial process is corrupted, and the defendant may, as a result, be

deprived of a fair trial. 3

2 The General Assembly has recognized the cyclical nature of

domestic violence relationships. § 18-6-801.5, C.R.S. 2018.
3 Because the effect of the improper admission of the blind expert

testimony on the defendant’s right to a fair trial is the same, we
need not, and therefore do not, determine whether the prosecutor
had a good faith basis for presenting the blind expert testimony or,
instead, acted in violation of the special duties imposed on a

2
¶5 We conclude that virtually all of the blind expert testimony

presented in this case was wholly irrelevant to the issues properly

before the jury. We further conclude that the admission of this

evidence was highly prejudicial. Accordingly, we reverse the

convictions and remand for a new trial.

II. Facts and Procedural History

¶6 Kerry Lee Cooper and L.K. were in an intimate relationship

and living together at the time of the alleged assault. In the early

hours of a morning in the summer of 2013, L.K. woke up in a panic

attack. She felt like she could not breathe. It was very hot in the

room, so L.K. asked Cooper to plug in the nearby fan. Cooper

turned on the fan and placed it on the floor. L.K. was unhappy with

the positioning of the fan and the two began to argue.

¶7 According to L.K.’s testimony, Cooper then shoved the running

fan into L.K.’s face, cutting her face with the blades. 4 L.K. grabbed

prosecutor to seek justice, not just convictions. See Colo. RPC 3.8
cmt. 1; Domingo-Gomez v. People, 125 P.3d 1043 (Colo. 2005) (“[A]
prosecutor, while free to strike hard blows, is not at liberty to strike
foul ones.” (quoting Wilson v. People, 743 P.2d 415, 418 (Colo.
1987))).
4 L.K.’s statements and testimony on this point were inconsistent.

In statements to police officers immediately after the incident, she

3
a flashlight from the nightstand and hit Cooper on the head with it.

Cooper dropped the fan and began hitting L.K. in the face and ribs

with his closed fist. L.K. crawled to the window and screamed for

help. Cooper told L.K. to shut up and grabbed her by the jaw,

inserting his fingers into her mouth. She bit one or more of his

fingers. Cooper then grabbed a tire iron located just outside the

bedroom and told L.K. to stop screaming or he would hit her with it.

When she did not, he hit her twice with the tire iron.

¶8 Cooper testified that he did not punch L.K., grab her jaw, or

pick up the tire iron and hit L.K. with it. According to him, L.K.

asked him to reposition the fan, and, when she became unhappy

with the way he had positioned it, he threw the fan on the end of

the bed, at which point L.K. hit him with the flashlight and bit his

hand when he attempted to take the flashlight away from her to

said that Cooper did not press the blades into her face. At trial, she
testified that Cooper did so, causing substantial injuries. There
were other inconsistencies in her testimony about the alleged
assault, including Cooper’s alleged use of a tire iron as a weapon.

4
protect himself. 5 Cooper did not deny, however, that he pushed L.K

in her forehead.

¶9 Cooper’s daughter, who lived close by, heard the screaming

and called the police. Officers obtained statements from Cooper

and L.K. and observed injuries on both of them.

¶ 10 At trial, over Cooper’s repeated objections, the prosecution

presented extensive testimony from an expert witness about (1)

characteristics of domestic violence relationships; and (2) the

“power and control wheel,” a tool developed purportedly to explain

the ways an abusive partner can use power and control to

manipulate a relationship.

¶ 11 The jury acquitted Cooper of the menacing and cruelty to

animal charges but convicted him of third degree assault and

harassment.

III. Claimed Errors

¶ 12 On appeal, Cooper asserts that (1) the trial court erred in

admitting the blind expert witness testimony both on reliability and

5 Cooper generally denied the charges, but also pleaded the

affirmative defense of self-defense. The trial court instructed the
jury on self-defense with respect to the third degree assault charge.

5
relevance grounds; (2) the prosecutor engaged in prosecutorial

misconduct during closing argument; and (3) the court committed

plain error when it did not give a special unanimity instruction on

the assault charge.

¶ 13 We agree that the expert testimony was inadmissible because

it was irrelevant and highly prejudicial; therefore, we reverse the

convictions and remand for a new trial. To provide guidance on

remand, we reject Cooper’s claim that he was entitled to a modified

unanimity instruction. We decline to address the alleged claims of

prosecutorial misconduct because we do not know whether those

statements will recur at the retrial.

IV. The Vast Bulk of the Blind Expert Testimony Was Irrelevant 6

¶ 14 Only relevant evidence is admissible. CRE 402. Irrelevant

evidence is not admissible. Id. The question here is whether expert

6 Because we conclude that the expert testimony was irrelevant, it

is unnecessary for us to address Cooper’s claim that the trial court
did not determine the reliability of the expert’s opinions before
allowing them to be presented to the jury. Our disposition also
obviates the necessity of addressing the Attorney General’s
objection to preservation of that issue.
If expert testimony is proffered at the retrial, the trial court
must comply with the gatekeeper obligations imposed on trial
courts by CRE 702 and the supreme court’s opinion in Ruibal v.
People, 2018 CO 98.

6
opinions regarding domestic violence had any relevance or “fit” to

the facts that were presented to the jury at trial.

¶ 15 To illustrate our analysis, the chart that appears in the

Appendix catalogues each opinion expressed by the expert witness

and the historical evidence, if any, presented to the jury that had

any relationship to the expressed opinion.

A. Standard of Review

¶ 16 We review a trial court’s evidentiary ruling for an abuse of

discretion. People v. Welsh, 80 P.3d 296, 304 (Colo. 2003). A trial

court abuses its discretion if its ruling is manifestly arbitrary,

unreasonable, or unfair, id., or if it misconstrues or misapplies the

law, People v. Glover, 2015 COA 16, ¶ 10.

B. Admissibility of Expert Testimony

¶ 17 CRE 702 governs the admission of expert testimony.

Exercising its gatekeeper function, the trial court must “focus on

the reliability and relevance of the proffered evidence” and

determine “(1) the reliability of the scientific principles, (2) the

qualifications of the witness, . . . (3) the usefulness of the testimony

to the jury,” and (4) whether the evidence meets the test of CRE

7
403. People v. Shreck, 22 P.3d 68, 70 (Colo. 2001). Recently, the

supreme court again explained the trial court’s gatekeeper function:

[T]he trial court’s inquiry should be broad in
nature and take into consideration the totality
of the circumstances of each specific case,
focusing on both the reliability and relevance
of the evidence. In light of the wide range of
factors that may be considered in any
individual case and the liberal nature of the
standard, we imposed upon trial courts
admitting evidence pursuant to CRE 702 an
obligation to first determine and make specific
findings on the record, not only as to the
reliability of the scientific principles upon
which the expert testimony is based and the
qualifications of the witness giving that
testimony, but also the usefulness of such
testimony to the jury, including specific
findings with regard to the court’s obligation
pursuant to CRE 403 to ensure that the
probative value of the evidence would not be
substantially outweighed by any of the
countervailing considerations enumerated in
the rule.

Ruibal v. People, 2018 CO 93, ¶ 12 (citations omitted).

¶ 18 Expert testimony should be admitted only when the expert’s

opinions will be helpful to the fact finder. People v. Valdez, 183

P.3d 720, 723 (Colo. App. 2008). “Helpfulness to the jury hinges on

whether the proffered testimony is relevant to the particular case:

whether it ‘fits.’” People v. Martinez, 74 P.3d 316, 323 (Colo. 2003).

8
Fit demands more than simple relevance; it
requires that there be a logical relation
between the proffered testimony and the
factual issues involved in the litigation. That
is, even if good grounds exist for the expert’s
opinion, it must be validly and scientifically
related to the issues in the case. That
particular expert testimony fits or is valid for
one facet or purpose of a proceeding does not
necessarily compel the conclusion that it fits
all facets. Therefore, the admissibility of
evidence must be evaluated in light of its
offered purpose.

Id. (citations omitted).

¶ 19 There are two substantial risks associated with the admission

of blind expert testimony. The first is that, as the supreme court

recognized in Venalonzo (and as the trial court explicitly recognized

in this case), most, if not all, expert testimony has the tendency to

bolster the credibility of one or more witnesses. Venalonzo, ¶¶ 32,

36. When an expert explains why a witness might have acted in a

counterintuitive manner, that explanation may bolster the

credibility of that witness. Id.

¶ 20 But, “while such ‘testimony may incidentally give rise to an

inference that a victim is or is not telling the truth about the

specific incident,’ ‘this fact alone is insufficient to deny admission of

the evidence, because expert testimony generally tends to bolster or

9
attack the credibility of another witness.’” Relaford, ¶ 30 (quoting

People v. Koon, 724 P.2d 1367, 1370 (Colo. App. 1986)). That is,

the bolstering effect is acceptable when the expert testimony is

necessary to educate the jury regarding matters about which the

ordinary juror has no knowledge. When that is not the case,

however, the bolstering effects of expert testimony are

unacceptable.

¶ 21 The second danger of blind expert testimony is that the jury

may find or infer that historical facts existed based solely on the

expert’s testimony, rather than on the historical evidence presented

to the jury. 7 On at least two occasions the supreme court has

recognized a similar danger in other contexts.

¶ 22 In the jury instruction context in Castillo v. People, 2018 CO

62, the supreme court addressed the first aggressor exception to

self-defense and, more specifically, whether an erroneously given

first aggressor instruction was harmless when there was no

7 An expert witness may rely on facts not in evidence when those

facts are “of a type reasonably relied upon by experts in the
particular field in forming opinions or inferences upon the subject.”
CRE 703. But here, the expert was a blind expert and, by
definition, knew nothing about the facts relating to the relationship
between Cooper and L.K.

10
evidence supporting the instruction. A division of this court had

reasoned that even if there was no evidence to support it, the error

was harmless because if there was no evidence to support the

instruction, the jury would simply disregard it. Id. at ¶ 47.

¶ 23 Rejecting that analysis, the supreme court stated that “we

have repeatedly expressed concern that jurors might try to fit facts

into an erroneously given instruction.” Id. at ¶ 59. As the supreme

court concluded in an earlier case, “[d]uring deliberations, it is

possible that the jury may have wondered why it was given the

instruction, decided that it must have been for some purpose, and

forced the evidence to fit the instruction, thereby denying

[defendant] his claim to self-defense.” Kaufman v. People, 202 P.3d

542, 562 (Colo. 2009). The Castillo court relied on its earlier

decision in Barnhisel v. People, 141 Colo. 243, 246, 347 P.2d 915,

917 (1959), where the court observed that an instruction which

correctly states the law but is not supported by evidence

erroneously “implies or assumes the existence of evidence not in the

record.”

¶ 24 The supreme court also explained that the danger of giving a

jury instruction that is not supported by the evidence is

11
“exacerbated by the prosecution’s misleading comments during its

closing argument.” Castillo, ¶ 60 (citation omitted). 8

C. The Expert’s Testimony Did Not “Fit” With the Factual
Evidence Presented

¶ 25 As stated above, expert testimony is only admissible when the

proffered testimony “fits” the factual issues involved in the case.

Martinez, 74 P.3d at 323. There was no such “fit” here.

¶ 26 No evidence presented to the jury proved or even suggested

that prior to the charged incident Cooper had assaulted, or

physically or nonphysically abused, L.K. 9 There was no evidence

that Cooper exercised improper control over L.K. physically,

emotionally, or economically. Nevertheless, the expert was

permitted to give extensive testimony about how domestic abusers

8 In a different context, the supreme court has held that evidence

that suggests a screening process was used in the filing of the
criminal case is improper because the jury is likely to infer that the
case is stronger if it survived these unknown screening procedures.
Domingo-Gomez, 125 P.3d at 1052-53.
9 Given that evidence of similar transactions of domestic violence

may be admissible in criminal prosecutions under section 18-6-
801.5, we presume that if the prosecutor in this case had
knowledge of any evidence of prior acts of domestic violence
between Cooper and L.K., she would have sought to admit such
evidence.

12
exercise such control and how that control contributes to or is

associated with the “power and control wheel.”

¶ 27 Neither was there any evidence of an escalating “cycle of

violence,” an attribute of many domestic violence cases and the

essence of the “power and control wheel” emphasized by the expert.

The only way the jury could have found that there was a pattern of

abuse was from the expert’s testimony — who, as a blind expert,

purportedly knew nothing about the facts of this case.

¶ 28 The expert also testified that victims of domestic abuse often

stay in abusive relationships and are then subjected to additional

abuse. If that opinion related to any material fact presented to the

jury in this case, the expert testimony might have been appropriate

because it is counterintuitive that an abused person would stay in

such a relationship. But, no evidence supporting that factual

scenario was presented to the jury. To the contrary, undisputed

evidence established that L.K. immediately moved out of Cooper’s

house after the charged incident and never returned. 10

10 The Attorney General also argues that the jury might have been

confused as to why it was necessary to subpoena L.K. to testify,
thus justifying at least some of the expert’s opinions. But any issue

13
¶ 29 We acknowledge that Cooper and L.K. were in an intimate

relationship. But, contrary to the argument made by the

prosecutor, and apparently accepted by the trial court, the

existence of that relationship alone does not justify the admission of

the “power and control wheel” and other expert testimony regarding

the characteristics of an abusive intimate relationship.

¶ 30 The Attorney General has not cited, and we have not found, a

single case that stands for the proposition that the mere existence

in this regard was of the prosecutor’s own creation. The jury heard
no testimony that L.K. had refused to testify at trial. Thus, whether
L.K. was under subpoena was wholly irrelevant to any legitimate
issue. Despite this irrelevance, the prosecutor herself asked L.K.
during direct examination if she was under subpoena. Subpoenaed
or not, she was present and testified at trial, and no evidence was
presented to the jury that she would not have been there if she had
not been subpoenaed.
Moreover, almost all conscientious lawyers subpoena their
witnesses, even when friendly, because if they do not and the
witness does not show up, a continuance is unlikely. See, e.g.,
People v. Dillon, 633 P.2d 504, 507 (Colo. App. 1981) (holding that
the trial court did not abuse its discretion in denying a continuance
where the defendant did not show that an attempt was made to
subpoena the witnesses before trial).
Similarly, the Attorney General’s argument that L.K. did not
want to be in court to testify proves too much and does not justify
the vast reach of the expert’s testimony. Few people want to be in
court to testify and, for many, testifying is a harrowing experience.
Nothing in the evidence presented to the jury indicates that L.K.
had, at any time, refused to cooperate with the police or the
prosecutor.

14
of an intimate relationship justifies the admission of this type of

expert testimony. The Attorney General’s reliance on People v.

Lafferty, 9 P.3d 1132 (Colo. App. 1999), is misplaced. There, the

court upheld “cycle of violence syndrome” testimony to explain the

victim’s recantation. Id. at 1134-35. But, as noted by the trial

court, L.K. never recanted.

¶ 31 Examination of the chart contained in the Appendix further

demonstrates that there was no record evidence that related to the

vast majority of the opinions expressed by the blind expert. Even if

some of the tangential opinions expressed by the expert were

arguably supported by the record (and we think it is a stretch to so

conclude), that very minor “fit” cannot excuse the admission of

extensive irrelevant evidence of this type. See CRE 403. This is

particularly the case when, as here, there were no third-party

witnesses to the alleged crimes, and Cooper’s criminal liability

rested entirely on the jury’s perception of the credibility of the

testifying fact witnesses.

¶ 32 For these reasons, we conclude that the trial court abused its

discretion in admitting the blind expert testimony.

15
D. The Improper Admission of the Expert Testimony Requires
Reversal

¶ 33 Our conclusion that the court erred in permitting the expert to

express opinions wholly irrelevant to the factual questions before

the jury does not end our inquiry. We must also determine whether

the admission of this testimony requires reversal. Hagos v. People,

2012 CO 63, ¶ 8.

¶ 34 Ordinarily, the erroneous admission of testimony is evaluated

under the harmless error standard. Pernell v. People, 2018 CO 13,

¶ 22. An appellate court reverses a criminal conviction only when

the wrongfully admitted evidence “substantially influenced the

verdict or affected the fairness of the trial proceedings.” Hagos,

¶ 12 (quoting Tevlin v. People, 715 P.2d 338, 342 (Colo. 1986)). In

evaluating whether the error requires reversal, the strength of

properly admitted evidence supporting the verdict is one important

consideration. Crider v. People, 186 P.3d 39, 43 (Colo. 2008). “If

that evidence overwhelmingly demonstrates the defendant’s guilt,

the error must be disregarded as harmless.” Ruibal, ¶ 17; accord

Pernell, ¶ 22.

16
¶ 35 Cooper claims, however, that he was deprived of a fair trial by

the admission of the blind expert testimony, and therefore, that we

should review his claims under the constitutional harmless error

standard. When a defendant specifically identifies a constitutional

right that is implicated by improperly admitted testimony and a

contemporaneous objection is made, an appellate court reviews for

constitutional harmless error. Hagos, ¶ 11. “These errors require

reversal unless the reviewing court is ‘able to declare a belief that

[the error] was harmless beyond a reasonable doubt.’” Id. (quoting

Chapman v. California, 386 U.S. 18, 24 (1967)). For this kind of

error, the prosecution bears the burden of proving the error was

harmless beyond a reasonable doubt. Id.

¶ 36 We need not determine whether the ordinary harmless error

standard of reversal or the constitutional harmless error standard

applies here because, for four reasons, we conclude that under the

more stringent harmless error standard, reversal is required. See

Hagos, ¶ 12 (“Reversal is more difficult to obtain under [the

harmless error] standard than under the constitutional harmless

error standard because [harmless error] requires that the error

17
impair the reliability of the judgment of conviction to a greater

degree than the constitutional harmless error standard requires.”).

¶ 37 First, the two critical issues for the jury to decide in this case

were who initiated the altercation and whether L.K. suffered bodily

injuries as a result of Cooper’s criminal conduct. As to the first

question, the jury had little to go on other than the testimony of

L.K. and Cooper.

¶ 38 Cooper presented two defenses at trial — general denial and

self-defense. He denied punching L.K., hitting her in the ribs, or

hitting her with a tire iron. Instead, he testified that when she hit

him on the head with the flashlight and bit his finger, he pushed

her away from him on the forehead. He did not deny using force

against L.K., but he did deny using the force L.K. alleged.

¶ 39 It was permissible for Cooper to present two alternative, if

perhaps inconsistent, defenses. People v. Wakefield, 2018 COA 37,

¶¶ 42-43. He was entitled to argue that the assault did not occur in

the way L.K. described, and that under his version of events his act

of pushing L.K. was done in self-defense. Simply because Cooper

denied L.K.’s version of events does not necessarily disprove his

defense of self-defense. See id.

18
¶ 40 Second, although there was no historical evidence presented

to the jury that Cooper and L.K. had a history of domestic violence,

the extensive expert testimony 11 regarding domestic violence may

well have caused the jury to infer that there was a prior history of

domestic violence and that Cooper’s alleged assault of L.K. resulted

from, or was explained by, that supposed abusive relationship.

Through the blind expert’s opinions, the prosecutor invited (indeed,

urged) the jury to speculate that there was a history of abuse or

violence even though the jury heard no such evidence from any

witness.

¶ 41 The dangers identified in Castillo (which are associated with a

jury instruction that finds no support in the evidence) are equally

present when a blind expert expresses opinions that find no

support in the historical facts presented to the jury. The jury may

have wondered why the prosecutor would spend so much time and

effort presenting these domestic abuse opinions, and why the court

would allow such opinions to be presented if L.K. and Cooper did

not have a history of domestic violence. The jury, therefore, could

11 The expert’s testimony consumes almost fifty pages of the

transcript in a trial that lasted less than two days.

19
have “decided that it must have been for some purpose, and forced

the evidence to fit [the expert opinions] thereby denying [Cooper] his

claim to self-defense.” Kaufman, 202 P.3d at 562. And, as in

Castillo, the prosecutor here extensively relied on the blind expert

testimony in her closing arguments.

¶ 42 Third, to the extent that the blind expert testimony invited the

jury to find nonexistent historical facts, the evidence was improper

CRE 404(b) evidence. Even more troubling, the trial court did not

require that evidence to withstand the rigors of the test of

admissibility under People v. Spoto, 795 P.2d 1314 (Colo. 1990).

Because the prosecutor never offered any specific other acts in

evidence, the trial court never made the threshold determination

that Cooper actually committed any of the acts which the expert

testimony invited the jury to infer. Id. at 1318. Because prior acts

of domestic violence suggest a person’s bad character, the

prosecutor was able to present improper character evidence about

Cooper without any of the protections required by section 18-6-

801.5, C.R.S. 2018, or Spoto.

¶ 43 Fourth, the expert testimony undermined Cooper’s credibility.

If Cooper and L.K. were in a violent domestic relationship, it is more

20
likely that Cooper committed the violent acts alleged by L.K. But,

as stated above, there was no evidence of a pre-existing violent

relationship. Therefore, the expert testimony improperly impeached

the credibility of Cooper’s denial of most of the alleged acts of

violence based on evidence that did not exist.

¶ 44 The operative question here is not whether the jury was

entitled to believe or disbelieve Cooper’s version of events regardless

of the admission of the expert testimony. Rather, we must

determine whether the improper testimony impermissibly affected

the jury’s verdict and the fairness of the trial proceedings. Hagos, ¶

12. For the reasons stated above, we conclude that the error in

admitting the irrelevant expert testimony “substantially influenced

the verdict [and] affected the fairness of the trial proceedings” and,

therefore, was not harmless. Id. (quoting Tevlin, 715 P.2d at 342).

We thus reverse Cooper’s convictions and remand for a new trial.

V. Issues That May Arise on Retrial

A. Jury Instructions

¶ 45 Cooper also contends that the trial court erred in not

instructing the jury on the requirement of unanimity. We reject

this argument.

21
1. Standard of Review and Applicable Law

¶ 46 We review jury instructions de novo to determine whether they

accurately informed the jury of the governing law. Riley v. People,

266 P.3d 1089, 1092 (Colo. 2011).

¶ 47 When a defendant is charged with crimes occurring in a single

transaction, the prosecutor need not elect among the acts, and the

trial court need not give a modified unanimity instruction. Melina

v. People, 161 P.3d 635, 639-40 (Colo. 2007).

2. The Trial Court Was Not Required to Instruct on Unanimity

¶ 48 The prosecutor charged Cooper with third degree assault

based on L.K.’s testimony that Cooper punched her in the face and

ribs on the night of the altercation. We agree with the Attorney

General that the allegations against Cooper concerned a short

timeframe, a single incident, and one victim. The evidence “does

not present a reasonable likelihood that jurors may disagree on

which acts the defendant committed” regarding the third degree

assault charge. Thomas v. People, 803 P.2d 144, 153 (Colo. 1990).

Therefore, Cooper was not entitled to a unanimity instruction.

22
B. Prosecutorial Misconduct

¶ 49 Cooper next contends that the prosecutor engaged in repeated

instances of prosecutorial misconduct during closing argument.

Because we do not know whether similar statements will be made

at the retrial, we decline to evaluate these statements.

¶ 50 We note, however, that a prosecutor has significant latitude to

comment on the strength and weakness of the evidence and to

employ reasonable rhetorical devices in doing so. Domingo-Gomez,

125 P.3d at 1048-49. Nevertheless, a prosecutor may not express

personal opinions regarding the credibility of any witness or opine

on the guilt of the defendant. Id. at 1049. Nor may the prosecutor

denigrate the defendant or his counsel. Id.

VI. Conclusion

¶ 51 The judgment of conviction is reversed, and the case is

remanded for a new trial.

JUDGE RICHMAN concurs.

JUDGE ROMÁN concurs in part and dissents in part.

23
JUDGE ROMÁN, concurring in part and dissenting in part.

¶ 52 I agree with the majority that allowing the testimony of the

domestic violence blind expert on the concept of “power and

control” was an abuse of discretion because it was irrelevant in this

case. No history of domestic abuse existed in the relationship

between defendant and the victim. As the majority notes, however,

this does not end our inquiry. And this is where I respectfully

depart from the majority’s analysis. Specifically, I dissent because,

on this record, the expert’s testimony was harmless.

¶ 53 Although defendant pled the affirmative defense of

self-defense, which is his right, he denied any involvement in all of

the victim’s injuries. Coupled with the contemporaneously taken

color photos of the victim’s injuries, the victim’s testimony, and the

testimony of law enforcement officers, the jury was well within its

right to simply not believe defendant’s account of what happened

regardless of the improper domestic abuse testimony. Thus, I

would conclude the error was harmless and affirm the jury’s

verdict.

24
¶ 54 Error in the trial process does not warrant the reversal of a

conviction if it can be shown to be harmless. People v. Summit, 132

P.3d 320, 327 (Colo. 2006). An appellate court will disregard the

error unless it “substantially influenced the verdict or affected the

fairness of the trial proceedings.” Hagos v. People, 2012 CO 63,

¶ 12 (quoting Tevlin v. People, 715 P.2d 338, 342 (Colo. 1986)). In

evaluating such error, the strength of properly admitted evidence

supporting the verdict is one important consideration. Crider v.

People, 186 P.3d 39, 43 (Colo. 2008). “If that evidence

overwhelmingly demonstrates the defendant’s guilt, the error must

be disregarded as harmless.” Ruibal v. People, 2018 CO 93, ¶ 17;

accord Pernell v. People, 2018 CO 13. 1

¶ 55 The jury was properly instructed on defendant’s affirmative

defense of self-defense, and no one argues to the contrary. Notably,

1 Here, the erroneously admitted evidence was limited to blind

expert testimony. The blind expert did not know details of the case,
had never met the parties, and testified generally about the
counterintuitive behavior of domestic abuse victims. She offered no
testimony that the charged crimes actually occurred, no opinion
that any witness was telling the truth about the assault, and no
statements that improperly vouched for the strength of the People’s
case. As will be seen, given the nature of the relationship between
this particular defendant and victim, her domestic abuse testimony
regarding “power and control” was irrelevant, but not prejudicial.

25
both the victim and defendant testified at trial. The victim testified

first, and her description of what happened put the issue of whether

defendant’s response was reasonable squarely in front of the jury.

¶ 56 The People presented the first-person testimony of the victim,

graphic color photographs of her injuries, and corroborative

testimony from responding officers. Specifically, in addition to the

color photographs, the victim’s injuries were testified to in great

detail, including:

• dried blood around the inside of her lips;

• one of her lips looking swollen;

• marks on her ribs;

• a “goosed out” bump on her head;

• another portion of her head looking “dented in”;

• visible bruises on her nose, around her eyes, and on her

ribs; and

• cuts on her face.

¶ 57 At this point, defendant could have acknowledged that he had

struck the victim but argued that his actions were reasonable and

in response to actions taken by the victim. This is the very essence

26
of the statutory defense of self-defense. Had he done so, I would

agree with the majority that the expert’s testimony on domestic

abuse highly prejudiced defendant’s affirmative defense claim of

self-defense because, in that scenario, the only way the jury could

have decided whether defendant acted in self-defense would have

been to analyze the contested evidence and consider the credibility

of both defendant and the victim. In that scenario, the irrelevant

testimony of the expert witness could well have prejudiced

defendant’s case.

¶ 58 But that’s not what happened. Instead, defendant took his

claim of self-defense off the table when he emphatically denied

touching the victim, other than a push on the forehead. The

following colloquy on cross-examination of defendant makes this

clear:

Q. So you pushed her on her forehead?

A. Yeah, I pushed her off like that (indicating).

Q. You didn’t punch her in the mouth?

A. No, I didn’t punch her in the mouth.

Q. You didn’t punch her in the ribs?

A. No, I didn’t punch her in the ribs.

27
Q. Or elbow her in the ribs?

A. No, ma’am, I didn’t.

Q. You didn’t grab her by the jaw?

A. No.

....

Q. So aside from pushing her in the forehead,
you never touched her?

A. No, ma’am.

¶ 59 In my view, this testimony removed the possibility of a

contested issue before the jury of whether self-defense was

appropriate in this case. This is because “[a] defendant asserting

self-defense as an affirmative defense admits that his use of force

satisfies the elements of the charged offense. But the defendant

also asserts that the otherwise unlawful use of physical force was

justified because it was reasonably necessary to defend himself or

another from the victim’s use or imminent use of force.” People v.

Tardif, 2017 COA 136, ¶ 37 (emphasis added).

¶ 60 This point was not lost on the jury, which was given the

following self-defense instruction.

It is an affirmative defense to the charge of
assault in the third degree that the defendant
used physical force upon another person, one,

28
in order to defend himself or another from
what he reasonably believed to be the use or
imminent use of unlawful physical force by the
victim; and, two, he used a degree of force
which he reasonably believed to be necessary
for that purpose.

The language of the jury instruction tracked the language of section

18-1-704(1) stating that a person acts in self-defense by “using

physical force upon another person to defend himself or a third

person from what he reasonably believes to be the use or imminent

use of unlawful physical force by that other person.” § 18-1-704(1),

C.R.S. 2018. But, here, when the jury applied the evidence to the

jury instruction, it must have realized that defendant’s self-defense

claim made no sense because (1) defendant testified he used no

physical force on the victim and (2) he testified to using no degree of

force rather than a reasonable degree of force in self-defense. In

other words, through his own testimony, defendant blew up his

self-defense theory. Rather than admit the crime charged yet seek

to justify or excuse his conduct, defendant’s testimony took it off

the table as an affirmative defense.

¶ 61 At this point, the jury was entitled to conclude that defendant

did not use a reasonable degree of force under self-defense law.

29
After all, rather than provide testimony as to why the force was

reasonable, defendant denied, in toto, assaulting the victim, which

was illogical under self-defense law, and which the People’s

admitted evidence at trial overwhelmingly refuted.

¶ 62 Of course, that still leaves defendant’s alternative defense to

these charges — straight denial. Here again, once examined in

isolation, and set next to the overwhelming and unrefuted evidence

presented by the People, I am left with the firm conviction that the

error in allowing the domestic violence expert’s opinion was

harmless.

¶ 63 As discussed, the overwhelming evidence of defendant’s guilt

in this case was established by properly admitted evidence. In the

face of this overwhelming evidence, I cannot find even a reasonable

possibility that the outcome of the trial would have been different

but for the expert’s opinion regarding the “power and control

wheel.” See Krustinger v. People, 219 P.3d 1054, 1063 (Colo. 2009)

(making clear that the “substantially influence” standard for

nonconstitutional error is a less onerous harmless error standard

than the “reasonable possibility” standard for constitutional error).

30
¶ 64 So, while I agree the admission of the expert testimony was an

abuse of discretion, I do not believe on this record that the expert’s

improper testimony “substantially influenced the verdict or affected

the fairness of the trial proceedings,” as required for

nonconstitutional harmless error. Summit, 132 P.3d at 327.

¶ 65 Because I conclude that the improperly admitted evidence was

harmless, I respectfully dissent from the majority’s decision to

reverse defendant’s convictions and remand for a new trial. In all

other respects, I agree with the majority.

31
Appendix

Opinion of Blind Expert Historical Evidence
Presented Relating to that
Opinion
Power and Control Wheel: How a None
person can abuse the other
person in a relationship without
ever physically touching them.
“So the first way that we talk None
about is emotional abuse, and
that’s name calling, put-downs,
you’re stupid, you’re fat, you’re
ugly, you can’t do anything right-
type of abuse.”
“Another form of abuse on that None
wheel is financial or economic.
And it’s very common for victims
of domestic violence to be — not
just be financially dependent on
their partner, but for the partner
to use that as a way to control
them, as a way to make sure that
they don’t have any power of
their own.”
“The next one is isolation. So it’s None
quite common for offenders to try
and isolate their victims from
their sources of support. So try
and put wedge in between their
relationships with family, friends,
maybe their church support,
whoever it is that supports them
the most.”
“The next thing on this wheel is None
minimizing, denying and
blaming. When we say that, very
often domestic violence offenders
will say things like, I didn’t do
that. Well, if I did it, I didn’t do
— it wasn’t really a big deal, and
it was probably her fault anyway.
So not taking responsibility for
their own behavior is quite
common.”
“The next thing on this chart is None
using children. So domestic
violence offenders know that it’s
really effective to threaten
children or try and manipulate
children in order to control their
victim.”
“The other thing on here is an Testimony from victim that she
attitude of male privilege. . . . only had one 10-by-14 foot
And by that, we mean that, you walk-in closet to store all of
know, generally I think people her things.
agree that in a healthy
relationship, you have two people Cooper testified that victim
that have equal say. . . . But in made him kick all the other
these relationships very often the people living in his house out
offenders have this attitude that of the house, and made them
I’m the king of the castle. I’m the move to the garage.
one who make the decisions. I’m
the one in charge.”
“So coercion and threats. It’s not None
at all uncommon for offenders to
make really specific and direct
threats, very clear. If you call the
police, if you tell anybody, if you
don’t do this or don’t do that,
then there will be this
consequence. So we see that
regularly.”
“Intimidation really falls on a None, other than testimony
spectrum. It can be something relating to the charged
very small like giving a person a incident.
look. Now, we all — you know,
that’s sort of a common thing in
relationships. You give each
other looks, and we sort of learn
how to read our partners. But
what domestic violence victims
will say is the look in this case
means uh-oh. There’s —
something really horrible is going
to happen. I may or may not
know what I’ve done, but this is
not going to be good.
Intimidation, though, can also be
really extreme, like taking out a
gun and waving it around
without ever actually making a
specific threat to do anything
with it. So that’s in a real quick
nutshell the power and control
wheel.”
Why victims don’t share what has Colloquy between prosecutor
happened: “Well, first of all, and victim establishing that
that’s really common for victims the victim did not “really want”
of domestic violence, to kind of to testify and that the
keep this secret and keep it quiet. prosecution had to subpoena
There are lots of reasons for that. her.
One of the most common reasons
that I hear is that they’re afraid,
that they’ve lived with this person
for a while and they absolutely
believe that this person has the
willingness and the capability to
carry out any threats that have
been made against them. And so
they — you know, out of a desire
to keep themselves or maybe
other people safe, they just keep
this to themselves. Another issue
is just that they’re extremely
embarrassed, ashamed,
humiliated.”
“Another reason is that very often Colloquy between prosecutor
people who go into abusive and victim that, at the time of
relationships have grown up in the charged incident, the
relationships where they’ve seen victim and her father were not
this kind of behavior modeled, on speaking terms.
and they — it’s sort of normalized
for them.”
“Another reason that I hear from Testimony from victim that in
victims is that they love this the beginning of their
person. You know, offenders are relationship Cooper was
not abusive 100 percent of the “sweet. He was one of those
time. If they were, that would charmers. I don’t know.
make it a lot easier. But very There were many things I liked
often they can be quite kind and about him. I like how kind he
loving and charming and caring was to not only me but other
and, you know, be a really good people. He seemed to have a
partner. big heart.”
In fact, one of the ways they’re
often described is as having a
Jekyll and Hyde personality. So
they’re — you know, can be this
really great, wonderful person,
and then this horrible ugly side
that they show. But because
they have that loving side and
that’s there enough of the time,
the victim in the relationship can
think, well, you know what? I’m
going to just sort of put up with
the bad things because I get
enough good things out of this
relationship.”
“But in this case, you have None
offenders who are driven by their
need for this power and control.
Like, I didn’t write it actually on
the board and I should have, but
when you look at this more
closely, you can see that power
and control at the core of this
illustration. And that’s really the
issue that offenders are dealing
with. Whenever they feel like
they’re losing some of their
power, they’re losing control over
their partner, that’s when they
use these or other physical
methods to gain that control.
That’s what drives their
behavior.”
Q: “Why would a victim keep Colloquy between prosecutor
talking to him?” and victim establishing that
A: “So, first of all, again, that’s after the incident, the victim
really common. I know it seems and Cooper spoke on the
confusing, but it’s not. It phone a number of times and
happens regularly. Almost that he “would tell me that he
everything that a domestic was sorry for what had
violence victim does, the thing happened. The remorse wasn’t
that drives their behavior is about what he had done to me.
keeping themselves safe. So It was more about us not
because they have been in this having the house and him
relationship, they’ve experienced being in jail.”
all of these different forms of
power and control, it often feels And colloquy establishing that
safer to them to be in the victim and Cooper
communication with their physically saw each other for
offender so they can sort of gauge half an hour one day, and
where that person is and gauge that, at that time, the victim
what their mood is like today. still had “feelings of love for
Am I going to be safe today? him.”
What are my next steps going to
look like? So a lot of it happens
because they’re trying to keep
themselves safe.
And, again, remember, these
guys are also — they have their
good side. They have their kind,
loving, charming side. That’s
usually the side that you see
after an abusive incident. So a
person being sorry and contrite
and sending gifts and flowers and
promising never to do it again
and go to counseling, that’s what
the victim wants, right? They
want to stay in the relationship
as long as there’s no more abuse.
And if that’s what they think
they’re going to get, that’s a
strong motivator.”
“In fact, the statistics show us or Testimony from victim that
tell us that a victim leaves an immediately after the assault
average of seven to nine times she moved out of Cooper’s
before they leave for good.” home and never moved back.

Q: “How does hurting a victim’s Conflicting testimony from
animal play into the power and victim that during the incident
control?” her dog came into the bedroom
A: “So there are a couple of and the dog “came at,” barked
answers to that. One is, it’s or growled at, or “lunged” at
really — it can be a really Cooper.
intimidating — we talked about
intimidation — it can be a really And, testimony from the
intimidating gesture to take, you investigating officer that the
know, a little cat or dog or horse dog “attempted to bite” Cooper.
or whatever it is, something that
the offender knows the victim
really loves and cares for and
hurt it. Like, that sends a really
strong message. Look what I’m
willing to do. Look at the lengths
I’m willing to go to. That sends
me a strong message, like uh-oh,
this person is dangerous and I
should be afraid.”
Q: “How could it also come into Colloquy between prosecutor
play in the power and control and victim that victim was not
aspect that the offender is maybe on speaking terms with her
decades older than the victim?” father at the time of the
A: “Well, as I mentioned, it’s not incident.
uncommon for people who have
grown up in abusive situations to
sort of find that again. And, you
know, in psychological terms, if
you’re trying to work out issues
with a parent in your mind, it
wouldn’t be at all uncommon to
find somebody who is sort of
similar in that way and try and
work it out in your current
relationship. So that could be
one explanation.”
Q: “Why might a victim after Testimony from victim that on
being physically abused and the night of the incident she
offered medical treatment refuse did not receive medical
to go into treatment that day to treatment, but that she did
be taken away to treatment?” eventually go to a doctor.
A: “Well, there could be a number
of answers to that. So it could be
that they are scared. They’ve
been told that, you know, if you
talk about this, if you tell
anybody, there will be a
consequence to that. And so
they want to sort of show their
solidarity with the offender. No,
I’m going to stay here. I’m going
to stay by that person’s side. It
could be — you asked about
animal abuse. It could be that
the pet or a child or somebody
else has been threatened and
they think, I need to stay here to
make sure nothing horrible
happens while I’m gone. It could
just be that they are minimizing
their own, I’m okay. I can handle
this. I don’t need to go to the
hospital. I’ll just sort of power
through it.”
Q: “Why might an offender tell a Colloquy between prosecutor
victim to stop yelling for help?” and victim establishing that on
A: “Well, I guess I might need a the night of the incident victim
little more context, but anytime yelled for help out the bedroom
— again, if an offender’s behavior window, and Cooper kept
is motivated by power and telling the victim to stop
control. So that’s just another yelling.
way to control a person. Literally
telling them what they can say
and what they can’t while they’re
being abused, that’s an ultimate
expression of power.”
Q: “How is this different from a None, apart from the factual
normal fight between a couple?” basis of the charged incident.
A: “So the distinction there is
what’s driving it. Because
everybody fights, right? All of us
have fights in our relationships;
that’s normal. So the distinction
is it becomes domestic violence
when there’s this patterned use
of these tactics. And you don’t
have to have all of the tactics, but
a patterned use of tactics that are
designed to coerce, manipulate,
control another person.”
Q: “Is it something that you see Testimony from the victim that
in domestic violence cases where Cooper asked her not to “come
the offender later asks the victim to court” at some point after
not to participate in court?” the incident
A. “Oh, that’s extremely
common.”