Peo v. Alvarado-Vasquez

23CA1491 Peo v Alvarado-Vasquez 07-31-2025

COLORADO COURT OF APPEALS

Court of Appeals No. 23CA1491
Arapahoe County District Court No. 20CR1295
Honorable Eric B. White, Judge

The People of the State of Colorado,

Plaintiff-Appellee,

v.

Mauricio Alvarado-Vasquez,

Defendant-Appellant.

JUDGMENT AFFIRMED

Division V
Opinion by JUDGE TAUBMAN*
Welling and Berger*, JJ., concur

NOT PUBLISHED PURSUANT TO C.A.R. 35(e)
Announced July 31, 2025

Philip J. Weiser, Attorney General, Allison S. Block, Assistant Attorney General,
Denver, Colorado, for Plaintiff-Appellee

Eric A. Samler, Alternate Defense Counsel, Hollis Whitson, Alternate Defense
Counsel, Denver, Colorado, for Defendant-Appellant

*Sitting by assignment of the Chief Justice under provisions of Colo. Const. art.
VI, § 5(3), and § 24-51-1105, C.R.S. 2024.
¶1 Defendant, Mauricio Alvarado-Vasquez, appeals his judgment

of conviction entered after a jury found him guilty of two counts of

first degree murder (after deliberation); first degree murder (felony

murder); three counts of conspiracy to commit first degree murder;

tampering with a deceased human body; tampering with evidence;

five counts of attempted first degree murder (after deliberation); two

counts of first degree assault; second degree assault; accessory to

crime; and racketeering under the Colorado Organized Crime

Control Act (COCCA). We affirm.

I. Background

¶2 From 2019 to 2020, law enforcement officials investigated two

cliques of the MS-13 gang in Aurora. As a result of this

investigation, Alvarado-Vasquez and nineteen codefendants received

multiple charges related to a series of criminal episodes allegedly

executed by the cliques. The charges included several counts of

first degree murder, conspiracy to commit first degree murder,

tampering with evidence, first degree assault, unlawful distribution

of cocaine, and COCCA violations, among others.

¶3 The two cliques were known as Leeward Locas Salvatrucha

(LLS) and Gutierrez Locas Salvatrucha (GLS). Their rival gang was

1
the 18th Street gang. Josue Tobia-Carbajal and David Tobia-

Carbajal1 led the GLS faction. Alvarado-Vasquez headed the LLS

faction.

¶4 Alvarado-Vasquez’s twenty-five2 charges stemmed from the

following four criminal episodes of which a reasonable jury could

find the following facts:

Murder of V.D.

¶5 V.D. had been associated with the 18th Street gang in

California. On September 7, 2019, she and her friend were at

Lempira, an Aurora bar and nightclub. V.D. went outside to her

Jeep after a GLS/LLS associate asked her to give him a cigarette.

As she was leaning into her car to retrieve one, David and Alvarado-

Vasquez approached. With a knife held to her throat, V.D. was

forced into her Jeep. Then, her Jeep and other cars containing

GLS/LLS associates caravaned to Josue’s house. There, David and

1 We refer to these brothers throughout this opinion by their first

names, rather than their shared last name, to avoid confusion.
2 In addition to the eighteen charges listed above, and two charges

of which he was acquitted, Alvarado-Vasquez was convicted of an
additional five counts of enhanced sentencing under our crime of
violence statute. He does not appeal these convictions.

2
Alvarado-Vasquez stabbed V.D. to death. V.D.’s body was found in

a burning car on the side of an interstate highway the next day.

Murder of C.R.

¶6 On November 2, 2019, David and GLS/LLS associates were at

Lempira when David instructed them to watch C.R., another 18th

Street gang member. After the bar closed, C.R. left in his car.

Several GLS/LLS associates, Alvarado-Vasquez, and David followed

him in their own cars. C.R.’s car turned, David and Alvarado-

Vasquez’s car followed it, and then Alvarado-Vasquez shot C.R.

Drive-by Shooting

¶7 On November 11, 2019, after a night at Lempira, six people,

including 18th Street gang members, left the nightclub in their car.

GLS/LLS members, including Alvarado-Vasquez, followed them in a

black SUV. When the car containing 18th Street gang members

pulled over to let the GLS/LLS SUV pass, Alvarado-Vasquez fired

shots into the car, hitting several of its passengers.

Conspiracy to Commit Murder of A.P.

¶8 From October to November 2019, Alvarado-Vasquez and Josue

asked a waitress to set up a meeting with A.P., an 18th Street gang

member. They explained to the waitress that they wanted to kill

3
A.P. She informed them where A.P. would be one night, and

Alvarado-Vasquez and Josue went to look but did not find him.

COCCA Charge

¶9 To prove the COCCA charge, the prosecution presented expert

testimony about the origins and structure of MS-13. Additionally, it

presented evidence of an uncharged murder, witness testimony,

and other evidence to prove the individuals charged operated as a

gang.

¶ 10 After a sixteen-day trial, Alvarado-Vasquez was convicted on

all counts but two. He was sentenced to two consecutive life

sentences without the possibility of parole in the custody of the

Department of Corrections for the three first degree murder

convictions. For the others, the court sentenced Alvarado-Vasquez

to more than 400 years in prison.

¶ 11 Alvarado-Vasquez now appeals, arguing the trial court erred

when it (1) admitted evidence of an uncharged homicide to prove

the COCCA charge; (2) denied his motion to suppress; (3) admitted

certain expert testimony; and (4) denied his tendered implicit bias

jury instruction.

4
II. Evidence of Uncharged Murder

¶ 12 Alvarado-Vasquez maintains the trial court erred when it

admitted evidence of an uncharged murder because it was not

relevant and was unduly prejudicial. We disagree.

A. Applicable Law and Standard of Review

¶ 13 Intrinsic acts, exempt from the evidentiary rule governing

admission of other crimes evidence, include acts that directly prove

the charged offense. Rojas v. People, 2022 CO 8, ¶ 52, 504 P.3d

296, 309. As with all evidence, intrinsic act evidence must be

relevant — having any tendency to make the existence of any fact

that is of consequence to the determination of the action more

probable or less probable than it would be without the evidence —

to be admitted. CRE 401. However, even relevant evidence may be

excluded if its probative value is substantially outweighed by the

dangers of unfair prejudice or, among other reasons, “by

considerations of undue delay, waste of time, or needless

presentation of cumulative evidence.” CRE 403.

¶ 14 A person is guilty of violating the COCCA statute if that person

is “employed by, or associated with, any enterprise” and “knowingly

conduct[s] or participate[s], directly or indirectly, in such enterprise

5
through a pattern of racketeering activity.” § 18-17-104(3), C.R.S.

2024. “Pattern of racketeering” means engaging in at least two acts

of racketeering activity, which are related to the conduct of the

enterprise. § 18-17-103(3), C.R.S. 2024. An “enterprise” is

“any . . . group of individuals, associated in fact although not a legal

entity, and shall include illicit as well as licit enterprises and

governmental as well as other entities.” § 18-17-103(2).

“Racketeering activity” means actions to commit, to attempt to

commit, to conspire to commit, or to solicit, coerce, or intimidate

another person to commit, among other things, murder. § 18-17-

103(5)(b)(I).

¶ 15 A COCCA associated-in-fact enterprise must have “at least

three structural features: a purpose, relationships among those

associated with the enterprise, and longevity sufficient to permit

these associates to pursue the enterprise’s purpose.” McDonald v.

People, 2021 CO 64, ¶ 44, 494 P.3d 1123, 1131 (quoting Boyle v.

United States, 556 U.S. 938, 946 (2009)). The existence of the

enterprise must be proved apart from the charged pattern of

racketeering activity. Id. at ¶ 45, 494 P.3d at 1131.

6
¶ 16 We review a trial court’s evidentiary ruling for abuse of

discretion. Bondsteel v. People, 2019 CO 26, ¶ 45, 439 P.3d 847,

854. A court abuses its discretion when its ruling is manifestly

arbitrary, unreasonable, or unfair. Id. We review nonconstitutional

errors that were preserved by objection for harmless error. Hagos v.

People, 2012 CO 63, ¶ 12, 288 P.3d 116, 119. Under this standard,

reversal is required only if the error substantially influenced the

verdict or affected the fairness of the trial proceedings. Id.

B. Additional Facts

¶ 17 To prove that the GLS/LLS factions operated as a criminal

enterprise, the prosecution introduced evidence of the uncharged

murder of M.G.G. in February 2019. Jurors heard testimony that

two members of GLS/LLS stabbed to death M.G.G., a member of

the 18th Street gang, to achieve a higher rank in MS-13. Alvarado-

Vasquez was not involved in that incident.

¶ 18 The prosecution argued that the incident proved one of the

necessary elements in its COCCA charge — the existence of the

criminal enterprise separate and apart from the criminal charges

before the court. The trial court agreed and admitted evidence of

the incident as long as its presentation included the promotion of

7
GLS/LLS members within MS-13 because of the murder. It also

issued contemporaneous limiting instructions. These instructions

told the jury that Alvarado-Vasquez was not charged with the

murder of M.G.G. and to consider the evidence only to determine if

an enterprise existed under the COCCA charge.

C. Analysis

¶ 19 Alvarado-Vasquez argues the court’s admission of evidence of

M.G.G.’s murder was not relevant because it did not make it more

probable that he was associated with a criminal enterprise.

Moreover, he contends the evidence was cumulative, and therefore

unduly prejudicial, in light of the prosecution’s other evidence. We

disagree.

¶ 20 The evidence related to M.G.G.’s murder was highly relevant

because it was an intrinsic act proffered to prove that GLS/LLS

operated as an “enterprise” under the COCCA statute. Contrary to

Alvarado-Vasquez’s contention, his lack of association with

M.G.G.’s murder was a key factor in its relevancy. The prosecution

needed to show the GLS/LLS factions had engaged in a pattern of

criminal activity beyond the alleged criminal episodes involving

Alvarado-Vasquez. McDonald, ¶ 46, 494 P.3d at 1132 (“In other

8
words, although a COCCA associated-in-fact enterprise may exist

only to commit the pattern of racketeering activity, it must also

have an ongoing organization of associates functioning as a

continuing unit that ‘unit[es] its members in a cognizable group’

beyond the fact that its members committed the predicate crimes,

Nelson v. Nelson, 833 F.3d 965, 968 (8th Cir. 2016) . . . .”).

Although Alvarado-Vasquez was not charged with M.G.G.’s murder,

this evidence demonstrated that the GLS/LLS cliques’ pattern of

activity existed beyond the other offenses with which he was

charged.

¶ 21 M.G.G.’s murder also met the three required elements stated

in McDonald. Id. at ¶ 44, 494 P.3d at 1131 (explaining an

enterprise must have “a purpose, relationships among those

associated with the enterprise, and longevity sufficient to permit

these associates to pursue the enterprise’s purpose” (quoting Boyle,

556 U.S. at 946)). The incident illustrated that the GLS/LLS

factions operated as a purposeful, cognizable group, given that the

members performed a common criminal activity: committing

murders of 18th Street gang members to increase their status in

MS-13. Further, the associates involved in M.G.G.’s murder were

9
also shown, through other evidence, to have relationships or direct

involvement with the GLS/LLS associates involved in Alvarado-

Vasquez’s related criminal activity. Finally, longevity was indicated

because M.G.G.’s murder predated any of the criminal episodes

charged in the case at hand.

¶ 22 Nevertheless, Alvarado-Vasquez contends that a “gang

manifesto” later found in his duffel sufficiently proves COCCA’s

enterprise element, making the evidence related to M.G.G.’s murder

less probative, inflammatory, and cumulative. However, Alvarado-

Vasquez later contradicts himself, stating that “the only [piece of

evidence of] evidentiary value found in the duffel bag was the

firearm.” To the extent Alvarado-Vasquez means the photo of a

“gang manifesto” found on his phone, it is not a clear evidentiary

substitute. It does not show how GLS/LLS members “functioned as

a continuing unit” or how long the cliques had been in existence.

Id. at ¶ 42, 494 P.3d at 1131-32 (quoting Boyle, 556 U.S. at 943).

¶ 23 Likewise, as long as admitted evidence adheres to Colorado’s

Rules of Evidence, it is immaterial if the “gang manifesto” could

have been substituted for evidence of M.G.G.’s murder. People v.

Morales, 2012 COA 2, ¶ 9, 298 P.3d 1000, 1003 (“The prosecution

10
is generally entitled to prove the elements of its case against a

defendant by evidence of its own choice . . . .”).

¶ 24 For his remaining contentions that various expert and witness

testimony make the admission of M.G.G.’s murder unduly

prejudicial, Alvarado-Vasquez provides no record citations to this

alleged testimony. Therefore, we do not consider these arguments.

C.A.R. 28(a)(7); see Black v. Black, 2018 COA 7, ¶ 67, 422 P.3d 592,

604; O’Quinn v. Baca, 250 P.3d 629, 631-32 (Colo. App. 2010)

(holding that “parties ‘should not “expect [an appellate] court to

peruse the record without the help of pinpoint citations”’” (quoting

L.S.F. Transp., Inc. v. NLRB, 282 F.3d 972, 975 n.1 (7th Cir. 2002))).

11
III. Duffel Bag

¶ 25 Alvarado-Vasquez next contends the trial court erred by using

the independent source doctrine to uphold the search of his duffel

bag.3 We are not persuaded.

A. Additional Facts

¶ 26 In December 2019, law enforcement officials located Alvarado-

Vasquez at a Gunnison motel, where he was staying while working

in a temporary construction job. Acting on an arrest warrant, a

coalition of local, state, and federal law enforcement officers

arrested him in the motel’s hallway. Law enforcement officials then

conducted a protective sweep for other individuals in his motel

room based on the allegations of violent crimes and gang affiliations

against Alvarado-Vasquez. No one was found in the room, but

officers noticed an open duffel bag in plain view. A necklace on top

3 Alvarado-Vasquez also argues that admission under the inevitable

discovery doctrine was inappropriate. Since he does not develop
this argument, we do not consider it. See People v. Mershon, 874
P.2d 1025, 1035 n.13 (Colo. 1994) (declining to address arguments
raised in a cursory, conclusory, or perfunctory fashion), abrogated
on other grounds by Melton v. People, 2019 CO 89; People v. Roberts,
2013 COA 50, ¶ 18 n.4, 321 P.3d 581, 585 n.4 (“A skeletal
‘argument,’ really nothing more than an assertion, does not
preserve a claim.” (quoting United States v. Dunkel, 927 F.2d 955,
956 (7th Cir. 1991))).

12
of it matched surveillance photos of Alvarado-Vasquez from

previous suspected criminal episodes. Looking further into the bag,

an officer saw a notebook, clothing, and what appeared to be the

back end of a firearm pistol grip. This officer then pulled open the

bag’s handles to “make sure [the bag was] safe to transport.” After

further opening the bag, officers confirmed that it contained a gun.

Without further disturbing or unloading the gun, officers seized the

bag and held it while they applied for a search warrant.

¶ 27 Several days later, the officers submitted a thirty-nine-page

affidavit for a search warrant of the bag’s contents. After a

magistrate granted the warrant, the officers retrieved the gun, and

the prosecution later connected it to the November 2 murder of C.R.

and the November 11 drive-by shooting incident.

¶ 28 Alvarado-Vasquez moved to suppress the gun and other items

seized from the duffel bag before his trial. Following a suppression

hearing, the trial court held that law enforcement officers had

conducted an unconstitutional search when they further opened

the bag after seeing the necklace. However, the court denied

Alvarado-Vasquez’s motion to suppress, holding the evidence

recovered from the duffel bag was admissible under the

13
independent source doctrine. It explained that the affidavit

submitted to support the warrant cited evidence linking the

observed documents, jewelry, and clothing, as well as the firearm,

to Alvarado-Vasquez. Therefore, the court reasoned, the officers’

affidavit showed their decision to seek a warrant was independent

of their observations during their illegal search for the gun.

¶ 29 Additionally, it explained that the affidavit’s description of the

larger investigation also gave officers a reason to search the duffel

bag apart from any mention of the gun. The trial court then found,

after excising references to officers’ observations or actions related

to the illegally discovered gun, that the magistrate who had issued

the warrant had a substantial basis for issuing the warrant given

that probable cause existed to search the duffel bag based on the

remaining information in the affidavit.

B. Standard of Review

¶ 30 When reviewing a suppression order, we defer to the trial

court’s findings of fact, if supported by the record; and we review its

legal conclusions de novo. People v. Miller, 75 P.3d 1108, 1111-12

(Colo. 2003). However, we review de novo whether a redacted

14
affidavit is sufficient to establish probable cause. People v. Hebert,

46 P.3d 473, 481 (Colo. 2002).

C. Applicable Law

¶ 31 The Colorado Constitution and the Fourth Amendment to the

United States Constitution protect people from unreasonable

governmental searches and seizures. Colo. Const. art. II, § 7; U.S.

Const. amend. IV; People v. McKnight, 2019 CO 36, ¶ 36, 446 P.3d

397, 406. Evidence obtained in violation of the Fourth Amendment

is subject to the exclusionary rule and must be suppressed from

presentation in the government’s case-in-chief. People v.

Schoondermark, 759 P.2d 715, 718 (Colo. 1988). The exclusionary

rule applies both to the illegally obtained evidence itself and to the

“fruit of the poisonous tree” — any other evidence derived from the

illegally obtained evidence. Id. (quoting Nardone v. United States,

308 U.S. 338, 341 (1939)).

¶ 32 However, the independent source doctrine is an exception to

the exclusionary rule. People v. Arapu, 2012 CO 42, ¶ 32, 283 P.3d

680, 687. This exception provides that “unconstitutionally obtained

evidence may be admitted if the prosecution can establish that it

was also discovered by means independent of the illegality.” Id. at

15
¶ 29, 283 P.3d at 686 (quoting People v. Morley, 4 P.3d 1078, 1080

(Colo. 2000)). Among other circumstances, the doctrine may apply

when evidence was initially discovered during an unlawful

warrantless entry or search but later seized (or re-seized) after the

police executed a valid search warrant. People v. Dominguez-Castor,

2020 COA 1, ¶ 20, 469 P.3d 514, 520.

¶ 33 To show that the warrant was genuinely an independent

source of the evidence, the prosecution must prove that (1) the

decision to seek the warrant was not prompted by what was

observed during the initial unlawful search; and, in situations

where law enforcement officers use evidence from the illegal search

to supply probable cause to support the search warrant, (2) the

magistrate had a substantial basis for issuing the search warrant

apart from the illegally obtained information. Id. at ¶ 21, 469 P.3d

at 520; Hebert, 46 P.3d at 481. A search warrant is validly issued

when probable cause exists supported by an oath or affirmation

particularly describing the place to be searched or the things to be

seized. Hebert, 46 P.3d at 482. “Probable cause exists when an

affidavit for a search warrant alleges sufficient facts to warrant a

person of reasonable caution to believe that contraband or evidence

16
of criminal activity is located at the place to be searched.” People v.

Quintana, 785 P.2d 934, 937 (Colo. 1990). The affidavit must

supply a “sufficient nexus between criminal activity, the things to

be seized, and the place to be searched.” People v. Kazmierski, 25

P.3d 1207, 1211 (Colo. 2001).

D. Analysis

¶ 34 Alvarado-Vasquez argues there was not a substantial basis for

the search warrant once information gleaned from the illegal search

was excised. He asserts that the affidavit’s reference to the

observed necklace, clothes, and notebook was not enough to cause

a reasonable person to believe that evidence of criminal activity

would be found in the duffel bag. Quintana, 785 P.2d at 937.

Moreover, he claims that the court erroneously relied on evidence

surrounding his arrest to justify the duffel bag search. Groh v.

Ramirez, 540 U.S. 551, 568 (2004) (explaining probable cause to

arrest a person will not itself justify a warrant to search his or her

property).

¶ 35 However, the affidavit demonstrates the necklace and

notebook provided a substantial basis for the warrant apart from

any gun-related evidence. It established that Alvarado-Vasquez had

17
worn a crucifix-style necklace like the one plainly visible in the

duffel bag on the night of V.D.’s murder. The affidavit included

surveillance photos showing that a car containing Alvarado-

Vasquez and other MS-13 associates had followed V.D.’s Jeep and

pulled into a gas station. In these photos, Alvarado-Vasquez,

wearing a black shirt and a crucifix-style necklace, entered the gas

station to purchase a cigarette lighter. Another MS-13 associate

purchased and filled a gas can. The car and Jeep were then seen

driving down the highway, the Jeep was set on fire, and the car

containing Alvarado-Vasquez left.

¶ 36 This evidence from the broader investigation linked Alvarado-

Vasquez with the crucifix-style necklace and V.D.’s murder, and

thus a person could reasonably infer that a bag containing a

crucifix-style necklace similar to the one worn at a crime scene

might contain further evidence from that incident. People v.

Hakel, 870 P.2d 1224, 1229 (Colo. 1994) (“[T]he link between

suspected criminal activity and a specific location to be searched

may be established by circumstantial evidence and proper

inferences drawn therefrom.”).

18
¶ 37 Moreover, the evidence surrounding the notebook provided an

additional basis for the magistrate to grant the request for the

search warrant. The detailed affidavit explained that Alvarado-

Vasquez consented to the search of his phone shortly after his

arrest. On his phone, officers found a photo showing a notebook

full of writings, in Spanish, describing, among other things, the

significance of MS-13 and other various words and symbols

associated with it. Seeing that the officers had also observed a

plainly visible notebook inside the duffel bag shortly before

Alvarado-Vasquez’s arrest, a reasonable person could have

“believe[d] that it contained a ‘gang manifesto’” or other relevant

evidence of MS-13 membership.

¶ 38 Therefore, given the affidavit’s presentation of the evidence

surrounding the necklace and the notebook, we conclude the trial

court did not err in finding the evidence admissible under the

inevitable discovery doctrine.

IV. Expert Testimony

¶ 39 Alvarado-Vasquez next contends the court abused its

discretion in admitting a firearm analyst’s opinion maintaining that

bullets found at the murder scene of C.R. and at the drive-by

19
shooting were fired from the gun found in Alvarado-Vasquez’s duffel

bag. We disagree.

A. Additional Facts

¶ 40 Prior to trial, Alvarado-Vasquez objected to the admission of

the prosecution’s firearms expert, Scott Webb of the Colorado

Bureau of Investigation. Specifically, he objected to Webb’s use of

firearms and toolmark analysis to determine if the firearm found in

the duffel bag was used in any of the charged criminal episodes.

¶ 41 Alvarado-Vasquez claimed the industry’s analytical methods

lacked sufficient reliability. The lack of reliability, he asserted, was

demonstrated in Strengthening Forensic Science in the United States:

A Path Forward (2009), a report by the National Research Council of

the National Academy of Sciences (NAS) that found that decisions of

toolmaker examiners were subjective, “based on unarticulated

standards and no statistical foundation for estimation of error

rates.” Id. at 153-54.

¶ 42 Specifically, the 2009 NAS report stated:

A fundamental problem with toolmark and
firearms analysis is the lack of a precisely
defined process. . . . AFTE [Association of
Firearm and Toolmark Examiners] has adopted
a theory of identification, but it does not

20
provide a specific protocol. It says that an
examiner may offer an opinion that a specific
tool or firearm was the source of a specific set
of toolmarks or a bullet striation pattern when
“sufficient agreement” exists in the pattern of
two sets of marks. It defines agreement as
significant “when it exceeds the best
agreement demonstrated between tool marks
know to have been produced by different tools
and is consistent with the agreement
demonstrated by tool marks known to have
been produced by the same tool.” The
meaning of “exceeds the best agreement” and
“consistent with” are not specified, and the
examiner is expected to draw on his or her
own experience. This AFTE document, which
is the best guidance available for the field of
toolmark identification, does not even
consider, let alone address, questions
regarding variability, reliability, repeatability,
or the number of correlations needed to
achieve a given degree of confidence.

Id. at 155.

¶ 43 Alvarado-Vasquez additionally pointed to Forensic Science in

Criminal Courts: Ensuring Scientific Validity of Feature-Comparison

Methods (2016), by the President’s Council of Advisors on Science

and Technology (PCAST), which found firearms analysis fell short of

foundational validity and the studies cited to support their work

were often “not appropriately-designed” and “underestimate the

false positive rate.” Id. at 106. He also cited several scholarly

21
articles and judicial decisions that recognized the limitations of

firearm and toolmark identification analysis.

¶ 44 After an evidentiary hearing under People v. Shreck, 22 P.3d

68 (Colo. 2001), to determine the admissibility of Webb’s testimony,

the court held the process of firearm and toolmark analysis was

reliable and admitted Webb as an expert. The court based its

admissibility decision on Webb’s explanation of the methodology

behind toolmark analysis and how the methodology was widely

accepted in the scientific community. Specifically, it highlighted

Webb’s testimony providing context to the studies cited by the

defense. Webb testified that the 2009 NAS report’s sole purpose

was to “see how we can further strengthen these sciences” and that

there were only “five pages dedicated to firearm toolmark

examination specifically.” He explained that “there [were] no

messages that this is junk science . . . it was just how can we

improve the testing.” Likewise, he testified that the 2016 PCAST

report also did not conclude firearm toolmark analysis was “junk

science” and asserted that toolmarks can be unique to different

tools and identified as such under certain magnification. Webb

added that a study done in response to the 2009 NAS report and

22
highlighted by the 2016 PCAST report, the 2014 Ames I study,

placed the field’s error rate at one percent. The court also cited

Webb’s testimony that firearm toolmark identification had been

around for more than 100 years and that his results and

conclusions were peer-reviewed by a second examiner. It noted that

Webb conceded, however, that there was no established conclusive

error rate despite the 2014 Ames I study’s findings.

¶ 45 At trial, Alvarado-Vasquez again objected to the reliability of

Webb’s testimony regarding toolmark identification and requested

the court limit the testimony as was done by the court in Abruquah

v. State, 296 A.3d 961, 969 (Md. 2023) (limiting the firearm expert’s

testimony to the AFTE categories of conclusiveness and prohibiting

testimony about the suspect’s weapon matching a certain bullet or

casing striations to any level of practical, ballistic, or scientific

certainty).

¶ 46 Alvarado-Vasquez explained that Abruquah, published after

the Shreck hearing, extensively analyzed and addressed the studies

and related arguments both parties had presented and concluded

that firearm and toolmark analysis could not reliably “support an

unqualified conclusion that such bullets were fired from a

23
particular firearm.” Id. at 968. He continued that the Abruquah

court noted the 2014 Ames I study and a second Ames study found

that if inconclusive results were factored into the purported error

rate, the error rates would jump to thirty percent and forty-four to

fifty-three percent, respectively. Likewise, Alvarado-Vasquez said

the Abruquah court found that a peer review process similar to the

one Webb outlined was subject to confirmation bias because the

second examiner “know[s] what the results of the first examiner

were.” He noted the two Ames studies were also not peer reviewed

or published in a journal, and the Abruquah court also found that

there was no evidence of general acceptance of AFTE’s methods

outside of firearms examiners or law enforcement officials.

¶ 47 However, the trial court declined to limit Webb’s testimony,

explaining that although Abruquah’s majority opinion was

persuasive, the defense was free to cross-examine Webb to better

highlight the purported unreliability of his methods and

conclusions. The court reasoned that the Abruquah decision was

not unanimous, and its two dissents were highly critical of the

majority’s holding that the trial court had erred, given that the

standard of review was abuse of discretion. Id. at 998 (Hotten, J.,

24
dissenting); id. at 1005 (Gould, J, dissenting). The court remarked

that it found the dissents’ take on the evidence well-reasoned when

one criticized the majority for engaging in an “extensive statistical

investigation,” id. at 1031 (Gould, J., dissenting), and the other

characterized the expert’s testimony rather as an expert opinion to

be weighted, id. at 1002-05 (Hotten, J., dissenting).

¶ 48 Alvarado-Vasquez’s reiterates these arguments on appeal.4

B. Applicable Law and Standard of Review

¶ 49 CRE 702 governs the admission of expert testimony. People v.

Glasser, 293 P.3d 68, 78 (Colo. App. 2011). Exercising its

gatekeeping function when deciding whether to admit expert

evidence, a 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

4 Alvarado-Vasquez also contends that his due process rights were

violated when “scientifically unreliable” testimony was admitted.
However, because we find the trial court did not abuse its discretion
in admitting Webb’s testimony, we do not reach his due process
argument. See People v. Genrich, 2019 COA 132M, ¶ 136, 471 P.3d
1102, 1122 (Berger, J., specially concurring) (Colorado appellate
courts have not previously considered whether the admission of
scientifically unreliable expert testimony results in a due process
violation).

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usefulness of the testimony to the jury,” and (4) whether the

evidence meets the test of CRE 403. Shreck, 22 P.3d at 70. A trial

court should apply a liberal standard that only requires proof that

the underlying scientific principles are reasonably reliable. Id. at

77. Determining if expert testimony is reasonably reliable requires

consideration of the totality of the circumstances surrounding the

proposed expert testimony and is not contingent on any specific

factors. Id. at 77-78. Therefore, certain factors — such as whether

the technique has been tested, whether it has been subjected to

peer review and publication, whether it has been generally

accepted, its known or potential rate of error, and the existence and

maintenance of standards controlling its operation — will be crucial

in some cases but inapposite in others. Kutzly v. People, 2019 CO

55, ¶ 12, 442 P.3d 838, 841-42 (referencing factors listed in

Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 593-94 (1993)).

The court may also consider the expert’s experience-based

specialized knowledge, as well as other factors. Shreck 22 P.3d at

77.

¶ 50 We review a trial court’s evidentiary rulings — such as rulings

on admission of expert testimony — for an abuse of discretion.

26
People v. Rector, 248 P.3d 1196, 1200 (Colo. 2011). A court abuses

its discretion when its decision is manifestly arbitrary,

unreasonable, or unfair, or is based on misapprehending or

misapplying the law. People v. Kendrick, 2017 CO 82, ¶ 36, 396

P.3d 1124, 1130.

C. Analysis

¶ 51 The crux of the defense’s argument mirrors the arguments

presented in Abruquah v. State, which a recent division of this court

specifically distinguished. People v. Rodriguez-Ortiz, 2025 COA 61,

¶¶ 57-61, ___ P.3d ___, ___. Alvarado-Vasquez also further

supplements his argument by citing another case announced after

briefing, which held firearms toolmark analysis is not “scientifically

valid.” State v. Adams, ___ P.3d ___, ___, 2025 WL 1553642, at *23

(Or. Ct. App. May 29, 2025).

¶ 52 While we acknowledge that throughout the country firearms

toolmark analysis is undergoing renewed scrutiny, e.g., United

States v. Ashburn, 88 F. Supp. 3d 239, 249 (E.D.N.Y. 2015); United

States v. Taylor, 663 F. Supp. 2d 1170, 1180 (D.N.M. 2009); United

States v. Glynn, 578 F. Supp. 2d 567 (S.D.N.Y. 2008); United States

27
v. Monteiro, 407 F. Supp. 2d 351, 372 (D. Mass. 2006), we find no

abuse of discretion here.

¶ 53 Colorado’s evidentiary standards for admitting expert

testimony differ from those applied by the courts in Abruquah and

Adams. As the Rodriguez-Ortiz division noted, the Abruquah court’s

standard mandates the application of Daubert factors while

Colorado’s standard permits but does not require consideration of

those factors. Rodriguez-Ortiz, ¶ 59, ___ P.3d at ___. Similarly, the

parties in Adams stipulated that firearms toolmark analysis was

“scientific evidence,” and therefore, the Adams court had to

determine if the evidence was “based on scientifically valid

principles” when performing its gatekeeping function. Adams,

___ P.3d at ___, 2025 WL 1553642, at *2; State v. O’Key, 899 P.2d

663, 673 (Or. 1995) (“[T]rial courts have an obligation to ensure

that proffered expert scientific testimony that a court finds

possesses significantly increased potential to influence the trier of

fact as ‘scientific’ assertions is scientifically valid.”).

¶ 54 To determine if expert testimony is reliable in Colorado, trial

courts must look at the totality of the circumstances. Shreck, 22

P.3d at 77. This inquiry makes no distinction between an inquiry

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into the validity of the evidence and one into its reliability. It

further makes no distinction between an inquiry into reliability as

used in the scientific community to mean repeatability and one into

reliability as a layman might use it to mean trustworthiness. See

Merriam-Webster Dictionary, https://perma.cc/Z4EC-5CZL

(defining “reliable”); see also Shreck, 22 P.3d at 73-79 (discussing

the merits of different evidentiary tests and concluding courts

should apply a totality of the circumstances inquiry). Rather, it

leaves the inquiry to the broad discretion of the trial court, which

may be deployed multiple ways, including in a manner similar to

that highlighted in Abruquah’s first dissent. Abruquah, 296 A.3d at

1000 (Hotten, J., dissenting) (“[T]rial judges are not required to

make a determination of the ultimate scientific validity of any

scientific propositions” but instead, absent scientific training, they

are tasked with ensuring that “sufficient indicia of legitimacy exist.”

(quoting Rochkind v. Stevenson, 236 A.3d 630, 649 (Md. 2020))).

¶ 55 Here, in part, Webb based his opinion on his training and

experience, which alone can substantiate admission. Brooks v.

People, 975 P.2d 1105, 1106 (Colo. 1999) (holding scent-tracking

evidence was experience-based specialized knowledge that was not

29
dependent on scientific explanation and determining the evidence

was admissible). Further, as highlighted by the Rodriguez-Ortiz

division, Webb’s testimony based on firearms toolmark analysis

satisfies many of the Daubert factors. Rodriguez-Ortiz, ¶ 63, ___

P.3d at ___ (listing cases that hold firearms toolmark analysis has

been meaningfully tested, subject to peer review and publication,

has an error rate, and has been generally accepted in the scientific

community).

¶ 56 Moreover, in contrast with the testimony by the expert in

Abruquah, Webb’s testimony was subject to numerous caveats. Id.

at ¶ 60, ___ P.3d at ___. Webb explained that any conclusions that

a firearm and a bullet matched were ultimately determinations that

experts decided based on their training and experience, and that

each expert could have a different understanding of what

constituted a sufficient match.

¶ 57 He admitted that his conclusions were not subject to peer

review and that his methods could not determine who had handled

the weapon at the time of the alleged crime. These caveats were, in

fact, elicited at trial during cross-examination, which is precisely

the way the Schreck court envisioned handling concerns about

30
invalid scientific assertions. Est. of Ford v. Eicher, 250 P.3d 262,

269 (Colo. 2011) (referencing Shreck, 22 P.3d at 78, and explaining

that testability and error rate concerns that implicate the reliability

of the evidence go to the weight of expert testimony, which are

matters that can be adequately addressed by vigorous cross-

examination, presentation of contrary evidence, and careful

instruction on the burden of proof).

¶ 58 We also distinguish this case from People v. Genrich, 2019

COA 132M, ¶ 31, 471 P.3d 1102, 1107 (Genrich II).5 There, the

defendant was convicted of multiple felonies, including two counts

of first degree murder, arising from a series of pipe bomb

detonations in 1991. Id. at ¶ 5, 471 P.3d at 1104. In his direct

appeal of the denial of his Crim. P. 35(c) petition, Genrich argued he

was entitled to an evidentiary hearing because his conviction was

based largely on toolmark analysis whose reliability had been

discredited by the studies discussed above. Id. at ¶¶ 1, 31-32, 471

P.3d at 1104, 1107-08. He explained that new evidence from the

5 We match the naming references that People v. Genrich, 2019 COA

132M, 471 P.3d 1102, set by identifying People v. Genrich, 928 P.2d
799 (Colo. App. 1996), as Genrich I.

31
2009 NAS report, as well as its author’s expert testimony, called

into question if “the exclusive sourcing of a tool mark to one

particular tool” was ever justified. Id. at ¶ 32, 471 P.3d at 1108.

The Genrich II court agreed that Genrich was entitled to an

evidentiary hearing and remanded the case to determine if the

admission of contrary expert testimony warranted a new trial. Id. at

¶ 64, 471 P.3d at 1113. On remand, after multiple experts testified

for and against the reliability of toolmark analysis, Genrich was

granted a new trial, and that decision was affirmed on appeal. See

People v. Genrich, 2025 COA 49, ¶¶ 35-38, 58, ___ P.3d ___, ___

(Genrich III).

¶ 59 The facts in Genrich II and III ultimately distinguish it if from

this case. First, the issue in the Genrich cases was the reliability of

an expert’s unqualified opinion regarding identification of marks on

a wire allegedly made by a hand tool. Genrich II, ¶¶ 21-23, 31, 471

P.3d at 1106-07. In contrast, this case involves an analysis of

marks left by a firearm on cartridge casings. The concurrence in

Genrich II explained that “[t]he analysis of toolmarks left on a

surface by a hand tool is inherently more subjective than the

analysis of toolmarks left by a gun on bullets or cartridge casings”

32
and therefore “[o]pinions from other jurisdictions concluding that

firearms identification testimony is admissible bear little weight

here because of the differences between toolmark identification

analysis for firearms and hand tools.” Id. at ¶ 125, 471 P.3d at

1120-21 (Berger, J., specially concurring). The facts of Genrich III,

which dealt with the government’s appeal of the postconviction

court’s order of a new trial after the remanded evidentiary hearing,

further buttress this distinction. Genrich III, ¶ 38, ___ P.3d at ___

(explaining experts opined hand-held toolmark analysis introduced

far more variables in the matching process and thus had a far less

statistical probability of identifying a correct match than firearms

toolmark analysis).

¶ 60 Second, during Genrich’s initial trial in 1991, the defense

counsel did not cross-examine the expert on the reliability of his

hand tool analysis methods or conclusions — presumably because

counsel lacked the 2009 NAS report, which was not issued until

eight years later. Genrich II, ¶ 28, 471 P. 3d at 1107. The lack of

cross-examination highlighting this conflicting evidence denied the

jury the opportunity to adequately weigh the reliability of the

expert’s testimony. In contrast, here, Alvarado-Vasquez not only

33
had the benefit of the 2009 NAS report during his trial, as well as

other reports, but his defense counsel also used these reports’

findings to guide their cross-examination of Webb.

¶ 61 Thus, given that there were still adequate legal and factual

grounds before it, we conclude the trial court did not abuse its

discretion when it admitted the testimony and let the jury

determine the appropriate weight to give Webb’s conclusion that the

gun found in the duffel bag was the same as the one used at the

alleged crime scenes.

V. Jury Instructions

¶ 62 Finaly, Alvarado-Vasquez alleges the court erred when it

denied his request to tender implicit bias instructions to the jury.

We are not persuaded.

A. Additional Facts

¶ 63 Alvarado-Vasquez is a Spanish speaker and an El Salvadoran

national without legal status accused of being an MS-13 gang

leader who participated in violent crimes. Citing the political

climate during the 2023 trial, Alvarado-Vasquez requested the court

tender the following instructions (or similar instructions) regarding

34
implicit bias, taken from the U.S. District Court for the Western

District of Washington.6

It is important that you discharge your duties
without discrimination, meaning that bias
regarding race, color, religious beliefs, national
origin, sexual orientation, gender identity, or
gender of the [plaintiff,] defendant, any
witnesses, and the lawyers should play no part
in the exercise of your judgment throughout
the trial. Accordingly, during this voir dire and
selection process, I [the lawyers] may ask
questions [or use demonstrative aids] related
to the issues of bias and unconscious bias.

¶ 64 The court refused to give the tendered instructions. After

Alvarado-Vasquez was convicted, the Colorado Supreme Court’s

Model Criminal Jury Instruction (COLJI) Committee amended its

model instructions to add language regarding unconscious bias.

COLJI-Crim. B:01 n.11 (2024).7

6 Alvarado-Vasquez also made other requests to the court regarding

implicit bias questioning during voir dire and education that were
also denied. However, he does not appeal these decisions.
7 After these briefings were before this court, the Colorado Supreme

Court adopted a rule change to Crim. P. 24(d), which addressed
when prospective jurors were preemptively challenged for implicit
bias, outlined procedures the trial court must undergo, and listed
certain factors it may consider when making its decision. The rule
is “simply intended to provide further guidance” and is not effective
until January 2, 2026. Rule Change 2025(15), Colorado Rules of
Criminal Procedure (Amended and Adopted by the Court En Banc,
June 26, 2025), https://perma.cc/PEB5-DQ89.

35
B. Applicable Law and Standard of Review

¶ 65 We review jury instructions de novo to determine whether, as

a whole, they accurately informed the jury of the governing law.

Riley v. People, 266 P.3d 1089, 1092-93 (Colo. 2011). If the jury

instructions properly inform the jury of the law, the trial court has

“broad discretion to determine the form and style of jury

instructions.” Day v. Johnson, 255 P.3d 1064, 1067 (Colo. 2011).

Accordingly, we review a trial court’s decision concerning a

proposed jury instruction for an abuse of discretion and will not

disturb the ruling unless it is manifestly arbitrary, unreasonable, or

unfair. Id.

¶ 66 When a defendant objects to the trial court’s ruling on a jury

instruction, we review for nonconstitutional harmless error and will

affirm if “there is not a reasonable probability that the error

contributed to the defendant’s conviction.” People v. Garcia, 28

P.3d 340, 344 (Colo. 2001) (quoting Salcedo v. People, 999 P.2d

833, 841 (Colo. 2000)).

C. Analysis

¶ 67 Alvarado-Vasquez acknowledges that, shortly after he was

convicted, a division of this court also affirmed a court’s refusal to

36
give an implicit bias instruction. People v. Toro-Ospina, 2023 COA

45, ¶ 47, 535 P.3d 132, 141-42 (finding no abuse of discretion

when no statute or case required the court to tender an implicit

bias jury instruction). Alvarado-Vasquez invites us to depart from

this decision because of the COLJI’s new implicit bias instruction.

We decline the invitation.

¶ 68 Courts are not bound by model instructions because they are

not law and not authoritative. People v. Salazar, 2023 COA 102,

¶ 22, 542 P.3d 1209, 1217. Therefore, the new COLJI instruction is

not a mandate, and the trial court would not have been required to

use it if it had been in effect at the time of trial.

¶ 69 Likewise, the record supports the conclusion that the court

did not abuse its discretion. The prosecution did not bring up

Alvarado-Vasquez’s immigration status, nor was he the only

Spanish speaker at trial because many of the witnesses called by

the People also only spoke Spanish. The court also provided a

reasoned explanation about its decision to deny the proffered

instruction. It noted that in nearby counties, Spanish-speaking

populations were the majority-minority, and it had not encountered

repeated instances of implicit bias. In lieu of the proffered

37
instructions, it agreed to give the jurors an instruction “that talk[s]

about sympathy, bias, and prejudice not having a place in the

courtroom” and noted that the attorneys were free to explore the

bias issue during voir dire.

¶ 70 While Alvarado-Vasquez now points us to several persuasive

authorities discussing the “uniquely difficult to identify” nature of

implicit bias, State v. Berhe, 444 P.3d 1172, 1178 (Wash. 2019), the

court used this rationale for its denial. The court said that it found

implicit bias to be a concept that was “not easy to understand” and

“not easy to identify,” and that providing the sort of instruction it

did can “scare the jurors into talking about how they really feel.” In

its experience, jurors were “not shy to disclose their views and their

biases” when an implicit bias instruction was lacking. Given these

reasons, we conclude the trial court did not abuse its discretion in

declining to give an implicit bias instruction.

VI. Disposition

¶ 71 We affirm Alvarado-Vasquez’s judgment of conviction.

JUDGE WELLING and JUDGE BERGER concur.

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