Asante-Chioke v. Dowdle et al

UNITED STATES DISTRICT COURT
EASTERN DISTRICT OF LOUISIANA
MALIKAH ASANTE-CHIOKE 	CIVIL ACTION
VERSUS 	NO. 22-4587
NICHOLAS DOWDLE ET AL. 	SECTION: “J”(3)
ORDER & REASONS
Before the Court are two motions: the first, a Motion to Exclude Plaintiff’s
Expert John C. Gardiner (Rec. Doc. 198) filed by Defendants Officers Johnathan
Downing, Gerard Duplessis, and Terry Durnin (“EJLD Defendants”); the second, a
Motion to Exclude the Testimony and Opinions of Dr. John Gardiner (Rec. Doc. 199)
filed by Defendants Col. Lamar A. Davis and Nicholas Dowdle (“LSP Defendants”).
Plaintiff filed an opposition to both motions. (Rec. Doc. 220). LSP Defendants filed a
reply. (Rec. Doc. 227). Having considered the motions and memoranda, the record,
and the applicable law, the Court finds that LSP Defendants’ motion is GRANTED
in part and DENIED in part, and that EJLD Defendants’ motion is DENIED.
LEGAL STANDARD
Federal Rule of Evidence 702 provides that a witness who is qualified as
an expert may testify if: (1) the expert's “specialized knowledge will help the trier of
fact 	to 	understand 	the 	evidence 	or 	to 	determine 	a 	fact 	in 	issue”; 	(2)
the expert's testimony “is 	based 	on 	sufficient 	facts 	or 	data”; 	(3)
the expert's testimony “is the product of reliable principles and methods”; and (4) the
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principles and methods employed by the expert have been reliably applied to the facts
of the case. Fed. R. Evid. 702. The United States Supreme Court's decision in Daubert
v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), provides the analytical
framework for determining whether expert testimony is admissible under Rule 702.
Both 	scientific 	and 	nonscientific expert testimony are 	subject 	to
the Daubert framework, 	which 	requires 	trial 	courts 	to 	make 	a 	preliminary
assessment of “whether the expert testimony is both reliable and relevant.” Burleson
v. Tex. Dep't of Criminal Justice, 393 F.3d 577, 584 (5th Cir. 2004); see also Kumho
Tire Co. v. Carmichael, 526 U.S. 137, 147 (1999).
When expert testimony is 	challenged 	under Daubert, 	the 	party 	offering
the expert's testimony bears the burden of proving its reliability and relevance by a
preponderance of the evidence. Moore v. Ashland Chem. Co., 151 F.3d 269, 276 (5th
Cir. 1998).
To be reliable, expert testimony must be based on “scientific knowledge,”
meaning it must be “ground[ed] in the methods and procedures of science” and based
on “more than subjective belief or unsupported speculation.” Daubert, 509 U.S. at
589-90. However, this rule does not require the testimony to be based on a scientific
study, but allows testimony based on “personal experience” if, in the trial court's
view, 	there 	is 	a 	sufficient 	level 	of 	“intellectual 	rigor” 	underlying
the testimony. Kumho Tire Co., 526 U.S. at 152. Indeed, “reliance upon extensive
personal 	experience 	or specialized knowledge 	is 	an 	acceptable 	ground for the
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admission of expert testimony.” Derouen v. Hercules Liftboat Co., LLC, No. CV 13-
4805, 2015 WL 13528499, at *3 (E.D. La. Sept. 4, 2015).
A number of nonexclusive factors may be relevant to the reliability analysis,
including: (1) whether the technique at issue has been tested; (2) whether the
technique has been subjected to peer review and publication; (3) the potential error
rate; (4) the existence and maintenance of standards controlling the technique's
operation; and (5) whether the technique is generally accepted in the relevant
scientific community. Burleson, 393 F.3d at 584. The reliability inquiry must remain
flexible, however, as “not every Daubert factor will be applicable in every situation;
and a court has discretion to consider other factors it deems relevant.” Guy v. Crown
Equip. Corp., 394 F.3d 320, 325 (5th Cir. 2004); see also Runnels v. Tex. Children's
Hosp. Select Plan, 167 F. App'x 377, 381 (5th Cir. 2006) (“[A] trial judge has
considerable leeway in determining how to test an expert's reliability.”).
With respect to the relevancy prong, the proposed expert testimony must be
relevant “not simply in the way all testimony must be relevant [pursuant to Rule
402], but also in the sense that the expert's proposed opinion would assist the trier of
fact to understand or determine a fact in issue.” Bocanegra v. Vicmar Servs., Inc., 320
F.3d 581, 584 (5th Cir. 2003). Ultimately, a court should not allow its “gatekeeper”
role to supersede the traditional adversary system, or the jury's place within that
system. Scordill v. Louisville Ladder Grp., LLC, No. 02-2565, 2003 WL 22427981 at
*3 (E.D. La. Oct. 24, 2003). As the Supreme Court noted, “vigorous cross-examination,
presentation of contrary evidence, and careful instruction on the burden of proof are
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the 	traditional 	and 	appropriate 	means 	of 	attacking 	shaky 	but 	admissible
evidence.” Daubert, 509 U.S. at 596. Generally, questions relating to the basis and
sources of an expert's opinion rather than its admissibility should be left for the jury's
consideration. United States v. 14.38 Acres of Land, 80 F.3d 1074, 1077 (5th Cir.
1996) (citing Viterbo v. Dow Chemical Co., 826 F.2d 420, 422 (5th Cir. 1987)).
PARTIES’ ARGUMENTS AND DISCUSSION
LSP Defendants argue that the Court should exclude Dr. Gardiner, along with
his testimony and opinions, because he is unqualified, his methodology is unreliable,
and his testimony is irrelevant. (Rec. Doc. 199-2, at 3).
EJLD Defendants make similar arguments, but they also argue that Dr.
Gardiner’s testimony will not help the factfinder. (Rec. Doc. 198-1, at 6).
I. 	Dr. Gardiner’s Qualifications
LSP Defendants argue that Dr. Gardiner is unqualified to opine on the likely
source of the shots fired because, apart from his expert reviews, he lacks specific
training, education, or experience analyzing bullet trajectory “based on gunshot
wounds.” (Rec. Doc. 199-2, at 6).
Plaintiff argues that Dr. Gardiner does have specific training and experience
to opine on the source of the bullet wounds because he has testified “about gunshot
sequences and attribution to specific shooters in federal court” and has conducted
“biomechanical analyses in ‘50 different cases’ involving gunshot wounds.” (Rec. Doc.
220, at 18 (citing Rec. Doc. 220-3, at 14–5)). Further, Plaintiff argues that Dr.
Gardiner 	is 	qualified 	to 	testify 	here 	because 	many 	courts 	have 	held 	that
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biomechanical 	engineers, 	including 	Dr. 	Gardiner, 	may 	rely 	on 	their 	technical
expertise to opine on gunshot attribution and sequencing without specific training,
education, or expertise in bullet trajectory analysis. (Rec. Doc. 220, at 17–8).
This Court agrees with Plaintiff. Dr. Gardiner holds a Bachelor of Science in
Mechanical Engineering and a Doctor of Philosophy in Bioengineering. (Rec. Doc.
198-3, at 4). He is a Senior Biomechanical Engineer who conducts “biomechanical
analysis of a variety of events including . . . shootings.” Id. He estimates that he has
performed biomechanical analyses in “50 different cases involving” gunshot wounds.
(Rec. Doc. 198-5, at 5). LSP Defendants offer no authority which requires Senior
Biomechanical Engineers to have specific training, experience, or education in bullet
trajectory analysis to opine on the source of each bullet wound. Further, courts have
allowed biomechanical engineers, including Dr. Gardiner, to opine on the source of
wounds in a shooting. Zuniga v. City of Los Angeles, No. 22-cv-3665, 2024 WL
4738212, at *2 (C.D. Cal. Sept. 18, 2024) (finding that Dr. Gardiner was qualified to
opine on which officer fired a bean bag round at plaintiff); Rodriguez v. Hunt et al.,
No. 18-cv-1640, 2025 WL 2648277, at *2 (D. Or. Sept. 16, 2025) (finding that a
biomechanical engineer was “qualified to testify on questions of biomechanical
engineering, including shooting reconstructions”). Accordingly, the Court finds that
Dr. Gardiner is qualified to opine on the likely source of Mr. Asante-Chioke’s gunshot
wounds.
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II. 	Reliability of Dr. Gardiner’s Methodology
LSP Defendants also argue that Dr. Gardiner’s methodology is unreliable
because he did not calculate or quantify the officers’ exact shooting angles. (Rec. Doc.
199-2, at 7). LSP Defendants contend that Dr. Gardiner merely “eyeballed” the body
camera footage to determine the source of each bullet wound. Id. at 9. According to
LSP Defendants, Dr. Gardiner must provide specific calculations or quantifications
of the shooting angles to have a reliable methodology. Id. at 7.
In contrast, Plaintiff contends that Dr. Gardiner did not merely “eyeball” the
footage and instead considered “the relative positions of each of the three officers to
Mr. Asante-Chioke, the gunshot wound entrances and exits, the gunshot wound
trajectories, and the anatomical postures and positions of Mr. Asante-Chioke during
the shooting incident.” (Rec. Doc. 220, at 20 (citing (Rec. Doc. 220-1, at 31))). Plaintiff
argues that these considerations are sufficient and that LSP Defendants cite no
authority which requires Dr. Gardiner to conduct a more rigorous analysis for his
methodology to be reliable.
This Court agrees with Plaintiff. LSP Defendants offer no authority which
requires an expert to quantify or calculate exact shooting angles to opine on shooting
source and position. Further, courts have found an expert’s methodology to be reliable
when those experts analyzed similar factors to the ones Dr. Gardiner analyzed in his
report. Davies v. City of Lakewood, No. 14-cv-1285, 2016 WL 614434, at *9 (D. Colo.
Feb. 16, 2016) (finding expert’s methodology reliable when that expert performed
“bullet trajectory analyses” and analyzed “various positions and poses of [shooting
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officer 	and 	decedent]” 	and 	“conduct[ed] 	bio-mechanical 	studies 	of 	potential
movements and poses to eliminate those which were unlikely”); Baker v. Coborn, 773
F. Supp. 3d 300, at 315 (N.D. Tex. 2025) (finding expert’s methodology reliable when
that expert “emphasized the relative firing positions and location of the [shooting
officers] in relation to the [decedent] as they shot at him”). Accordingly, this Court
does not find Dr. Gardiner’s methodology to be unreliable on those grounds.
LSP Defendants also argue that Dr. Gardiner’s methodology is unreliable due
to alleged inconsistencies and contradictions concerning the timing of certain wound
in his report termed as Gunshot Wounds #14 and #15 and his conclusions concerning
how many gunshot wounds were consistent with coming from Officer Dowdle during
the final 1.1 seconds of the shooting. (Rec. Doc. 199-2, at 9–14). However, as Plaintiff
correctly points out, LSP Defendants primarily dispute Dr. Gardiner’s conclusions,
not his methodology. Challenges to Dr. Gardiner’s conclusions are more appropriately
addressed at trial then at this stage of the litigation. As the Supreme Court has
explained, in reviewing pretrial challenges to expert testimony, this Court’s “focus, of
course, must be solely on principles and methodology, not on the conclusions that they
generate.” Daubert v. Merrell Dow Pharmaceuticals, Inc. 509 U.S. 579, 595 (1993).
“Vigorous 	cross-examination, 	presentation 	of 	contrary 	evidence, 	and 	careful
instruction on the burden of proof are the traditional and appropriate means of
attacking shaky but admissible evidence.” Id. at 596. Thus, this Court will not exclude
Dr. Gardiner’s testimony as unreliable based on these challenges.
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III. 	Relevance of Dr. Gardiner’s Opinions
Defendants argue that Dr. Gardiner’s opinions are irrelevant to the issue of
qualified immunity at this stage of the litigation. (Rec. Doc. 199-2, at 14; Rec. Doc.
198-1, at 6). LSP Defendants also suggest that Dr. Gardiner opines on ultimate
causation and damage issues regarding Gunshot Wound #15. (Rec. Doc. 199-2, at 14).
Plaintiff argues that Dr. Gardiner’s opinions are relevant to the issue of
qualified immunity because Dr. Gardiner opines on which shots Officer Dowdle likely
fired and the time that he likely fired them. (Rec. Doc. 220, at 15). Plaintiff also
contends that Dr. Gardiner’s opinions do not involve ultimate causation and damage
issues. Id.
This Court finds that most of Dr. Gardiner’s opinion is relevant. In his report,
Dr. Gardiner opines on the likely source of Mr. Asante-Chioke’s bullet wounds and
when the shooting officers, including Officer Dowdle, likely fired them. (Rec. Doc. 198-
3, at 33, 42). Such opinions are relevant to the pertinent qualified immunity issues of
“whether Dowdle fired any shots; how many if so; and when, in relation to Asante-
Chioke’s actions and death.” Asante-Chioke v. Dowdle, 103 F.4th 1126, 1131 (5th Cir.
2024). Further, at least one court has found a similar expert opinion relevant to the
issue of qualified immunity in excessive force cases. Cole v. Hunter, 68 F. Supp. 3d
628, 636 (N.D. Tex. 2014) (finding expert’s opinions on the “timing and sequence of
the gunshot wounds” relevant to whether shooting officers were entitled to qualified
immunity from excessive force claim). Accordingly, this Court will not exclude these
opinions on relevance grounds.
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Still, in his report Dr. Gardiner also references Chief Forensic Pathologist Dr.
Dana Troxclair’s conclusion that the “bullet causing Wound #15 killed Mr. Asante-
Chioke.” (Rec. Doc. 198-3, at 14). Opinions and references thereto concerning which
bullet killed Mr. Asante-Chioke are irrelevant to the limited issue of whether the
shooting officers are entitled to qualified immunity when they continued to fire upon
him. Accordingly, the Court will exclude such opinions and references from Dr.
Gardiner’s report.
IV. 	Helpfulness of Dr. Gardiner’s Opinions
EJLD Defendants also argue that Dr. Gardiner’s testimony will not assist the
factfinder because video captures the incident. (Rec. Doc. 198-1, at 6–7). EJLD
Defendants cite two cases to support their assertion. Id. (citing Carnaby v. City of
Houston, 636 F. 3d 183, 187 (5th Cir. 2011) (quoting Scott v. Harris, 550 U.S. 372,
381 (2007)).
Plaintiff argues that neither of EJLD Defendants’ cited cases mention the use
of experts or hold that experts cannot assist the factfinder in interpreting facts
depicted on video.
This Court agrees with Plaintiff. Neither Carnaby nor Scott addressed whether
the presence of video evidence renders expert testimony unhelpful. Carnaby only
discussed video evidence to articulate the legal standard by which the Fifth Circuit
reviews motions for summary judgement when video evidence exists: “Although we
review evidence in the light most favorable to the nonmoving party, we assign greater
weight . . . to the facts evident from video recordings taken at the scene.” Carnaby,
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636 F. 3d at 187. In Scott, the Supreme Court only explained that the Eleventh
Circuit should have viewed the facts in the light depicted by the video tape because
plaintiff’s version of events was “so utterly discredited by the record that no
reasonable jury could have believed him.” Scott, 550 U.S. at 380–81. No expert
testimony was challenged or mentioned.
By opining on the likely source and timing of each gunshot wound, Dr.
Gardiner will help the factfinder determine whether each of the shooting officers
acted unreasonably when they continued to fire upon Mr. Asante-Chioke. Therefore,
this Court will not exclude Dr. Gardiner’s testimony as unhelpful.
CONCLUSION
Accordingly,
IT IS HEREBY ORDERED that LSP Defendants’ motion (Rec. Doc.
199) is GRANTED in part and DENIED in part as follows. Dr. Gardiner will be
allowed to testify as an expert in this case, but he will not be able to opine or reference
opinions on which wound likely killed Mr. Asante-Chioke. The remainder of Dr.
Gardiner’s report and testimony is admissible.
IT IS FURTHER ORDERED that EJLD Defendants’ motion (Rec. Doc. 198)
is DENIED.
New Orleans, Louisiana, this 12th day of November, 2025.
CARL J. BARBIER
UNITED STATES DISTRICT JUDGE
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