Asante-Chioke v. Dowdle et al

1
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 is a Motion to Exclude the Testimony of John J. Ryan (Rec.
Doc. 206) filed by Plaintiff Malikah Asante-Chioke. Defendants Officers Johnathon
Downing, Gerard Duplessis, and Terry Durnin (collectively “EJLD Defendants”) filed
an opposition to the motion. (Rec. Doc. 216). Plaintiff filed a reply. (Rec. Doc. 234).
Having considered the motion, the legal memoranda, the record, and the applicable
law, the Court finds that the motion should be GRANTED in part and DENIED in
part.
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
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
Case 2:22-cv-04587-CJB-EJD Document 248 Filed 11/21/25 Page 1 of 10

2
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
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).
Case 2:22-cv-04587-CJB-EJD Document 248 Filed 11/21/25 Page 2 of 10

3
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
the 	traditional 	and 	appropriate 	means 	of 	attacking 	shaky 	but 	admissible
evidence.” Daubert, 509 U.S. at 596. Generally, questions relating to the basis and
Case 2:22-cv-04587-CJB-EJD Document 248 Filed 11/21/25 Page 3 of 10

4
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
Plaintiff argues that the Court should limit Mr. Ryan’s opinions regarding the
following: “impermissible legal conclusions,” “Defendants’ perception and reaction
times 	when 	assessing 	a 	threat,” 	and 	his 	opinions 	that 	“subjectively 	interpret
Defendants’ version of events.” (Rec. Doc. 206-1 at 6).
I. 	Legal Conclusions
Plaintiff argues that Mr. Ryan offers impermissible legal conclusions which
this Court should exclude. Id. Specifically, Plaintiff seeks to exclude Mr. Ryan’s
statement in his report which provides, “It is well known that [if] [sic] an officer
reasonably perceives an immediate threat of serious bodily harm or death against
themselves, another officer, or any third party, the officer may respond with deadly
force.” (Rec. Doc. 206-4 ¶ 339). Plaintiff notes that another court has excluded this
exact statement by Mr. Ryan in a different report. (Rec. Doc. 206-1, at 7 (citing
Sterusky v. Cooper, No. 22-cv-218, 2024 WL 4009668, at *7 (W.D. Ky. Aug. 30, 2024))).
EJLD Defendants argue that a full reading of Mr. Ryan’s opinion will explain
how this statement is based on Mr. Ryan’s “expertise in generally accepted [police]
policies, practices, training, and industry standards.” (Rec. Doc. 216, at 8).
While that may be the case, Mr. Ryan’s statement is not couched in the
appropriate terms. In Sterusky, the court excluded this exact statement because it
Case 2:22-cv-04587-CJB-EJD Document 248 Filed 11/21/25 Page 4 of 10

5
was “not couched in terms of police practices or training and, even if not intended as
such, constitutes a statement of law.” Sterusky v. Cooper, No. 22-cv-218, 2024 WL
4009668, at *7 (W.D. Ky. Aug. 30, 2024).
Experts may not provide legal standards because that job is reserved for the
Court. “There being only one applicable legal rule for each dispute or issue, it requires
only one spokesman of the law, who of course is the judge.” Askanase v. Fatjo, 130 F.
3d 657, 673 (5th Cir. 1997) (quoting Specht v. Jenson, 853 F. 2d 805, 807 (10th Cir.
1988)). Accordingly, the Court will exclude Mr. Ryan’s statement.
Plaintiff also argues that Mr. Ryan impermissibly opines on the standards set
forth in Graham v. Connor, 490 U. S. 386 (1989), applies those standards, and
concludes as to the reasonableness of Defendants’ actions using those standards.
(Rec. Doc. 206-1, at 8).
EJLD Defendants argue that the applicable police standards and practices in
this case parallel the mandates of Graham v. Connor. (Rec. Doc. 216, at 8–9). Thus,
EJLD Defendants contend that, while it may appear that Mr. Ryan is stating and
applying Graham v. Connor, he is stating and applying the relevant police standards
and practices of the instant case and determining whether the Defendants’ actions
comported with those standards and practices. Id. at 9.
This Court agrees with EJLD Defendants. In his report Mr. Ryan states
Officers throughout the United States are trained in two formulas with
respect to use of force decision-making and justification. The first of
these 	formulas 	is 	a 	three-part 	test 	that 	parallels 	the 	mandates
announced by the United States Supreme Court in Graham v. Connor.
The training directs officers to consider the seriousness of the offense;
whether or not the subject poses an immediate physical threat to the
Case 2:22-cv-04587-CJB-EJD Document 248 Filed 11/21/25 Page 5 of 10

6
officer or anyone else; and finally, whether the subject is actively
resisting or attempting to evade arrest by flight. I would note that in
writing policies for law enforcement agencies throughout the United
States, I use this three-factor test as the foundation of these policies. I
have noted in my auditing of law enforcement agencies as well as
through discussions during training, that the majority of agencies in the
United States use the three-factor test in policy and training. (Rec. Doc.
206-4 ¶ 331).
Mr. Ryan then applies these police standards and practices to this case to determine
that Officers Duplessis and Downing’s use of deadly force complied with those
standards. As this Court has explained, an expert may opine on whether officers
complied with applicable police policies and procedures. Gibbs v. Lopinto, No. 21-
1091, 2023 WL 3224581, at *3 (E.D. La. May 3, 2023) “Expert testimony regarding
[police] policies and procedures, and [officers’] compliance with those policies and
procedures, is admissible.” Id. (citing United States v. Warren, No. 10-154, 2010 WL
11623588, at *4 (E.D. La. Nov. 8, 2010)). The Court will not exclude Mr. Ryan’s
statements of applicable police standards and practices, nor his conclusion that
Officers Downing and Duplessis complied with those standards.
Plaintiff also suggests that Mr. Ryan needed to opine on relevant policies and
procedures of the East Jefferson Levy District for his opinion to be admissible. (Rec.
Doc. 206-1, at 9). Plaintiff argues that Joseph v. Doe, No. 17-5051, 2021 WL 2313475
(E.D. La. June 7, 2021) requires discussion of local police policies and standards. Id.
EJLD Defendants argue that Mr. Ryan does not need to discuss relevant East
Jefferson Levee District policies and procedures (Rec. Doc. 216, at 11), and this Court
agrees. In Joseph, the court did not hold that a use of force expert must opine on
relevant local police policies and procedures for their testimony to be admissible.
Case 2:22-cv-04587-CJB-EJD Document 248 Filed 11/21/25 Page 6 of 10

7
Further, Plaintiff fails to cite any authority which provides that adherence to local
police policies and procedures informs the constitutionality of an officer’s use of force.
To the contrary, the Eighth Circuit provides that “the constitution doesn’t rise and
fall with the whims of each police department’s policies.” Christiansen v. Eral, 52
F.4th 377, 379 (8th Cir. 2022) (explaining that just because an officer “chose to violate
department policy doesn’t mean that he acted unreasonably from a constitutional
perspective”). Accordingly, the Court will not reject Mr. Ryan’s testimony simply
because he failed to discuss the policies and procedures of the East Jefferson Levy
District.
Lastly, Plaintiff argues that Mr. Ryan offers impermissible legal opinions
because he opines that the EJLD Defendants acted reasonably. (Rec. Doc. 206-1, at
4). While reasonableness is an inadmissible legal conclusion, Plaintiff fails to offer
specific examples from Mr. Ryan’s report where he opines on the reasonableness of
the EJLD Defendants’ actions. However, if Mr. Ryan attempts to testify at trial on
the reasonableness of the EJLD Defendant’s actions, the Court will exclude such
testimony.
II. 	The “Reactionary Gap”
Plaintiff also argues that Mr. Ryan is unqualified to opine on the “reactionary
gap” between when an officer receives a stimulus to stop or start firing and when an
officer responds to said stimulus. (Rec. Doc. 206-1, at 12). Plaintiff argues Mr. Ryan
is unqualified because he lacks field training in this area. Id. EJLD Defendants argue
that Mr. Ryan is qualified to opine on reaction time because he has spent numerous
Case 2:22-cv-04587-CJB-EJD Document 248 Filed 11/21/25 Page 7 of 10

8
hours training officers in shooting scenarios, including conducting stimulus drills on
a shooting range.
This Court agrees with EJLD Defendants. As Mr. Ryan explains in his report,
when training officers, he has “conducted stimulus drills on the range whereby
officers are given stimulus to commence firing and stimulus to cease firing” to
evaluate each shooting officer’s reactionary gap. (Rec. Doc. 206-4 ¶ 340). As another
court has noted, Mr. Ryan has conducted such reaction training over 100 times. Estate
of Smart v. Chaffee, No. 14-2111, 2020 WL 7643505, at *13 (D. Kan. Dec. 23, 2020)
(finding Mr. Ryan qualified to opine on the reactionary gap because “[i]n training
police officers nationwide, Mr. Ryan has conducted reaction-time firearms training
more than 100 times. This training sometimes involved asking police officers to stop
shooting at a target when a simulated threat was removed, such as the target being
turned sideways to the shooting officer.”) Accordingly, this Court finds Mr. Ryan
qualified to opine on the reactionary gap.
Plaintiff also argues that, even if Mr. Ryan were qualified, his opinions on the
reactionary gap will not help the factfinder because perception reaction times are
common sense. (Rec. Doc. 206-1, at 13). However, this Court disagrees. While a lay
person may have a general understanding of perception reaction times, “[a] lay person
typically would not have experience or knowledge about the time it takes an officer
to react to a perceived threat or the absence of a perceived threat.” Estate of Smart v.
Chaffee, No. 14-2111, 2020 WL 7643505, at *14 (D. Kan. Dec. 23, 2020). By opining
that shooting officers take time to react to a stimulus to stop shooting, Mr. Ryan may
Case 2:22-cv-04587-CJB-EJD Document 248 Filed 11/21/25 Page 8 of 10

9
help the factfinder determine whether the Defendants officers’ actions to continue
shooting Mr. Asante-Chioke were reasonable. Consequently, this Court will not
exclude Mr. Ryan’s testimony as unhelpful.
III. 	Mr. Ryan’s Factual Interpretations
Plaintiff also argues that this Court should exclude “Mr. Ryan’s opinions that
merely recite defense counsel’s factual and legal narratives.” (Rec. Doc. 206-1, at 14).
EJLD Defendants argue that Mr. Ryan’s opinions are not based on defense counsel’s
factual and legal narratives, but instead are based on his view of the body cam, dash
cam, and bystander video evidence. (Rec. Doc. 216, at 12).
This Court agrees with EJLD Defendants. As Mr. Ryan explains, “[m]y
methodology in preparing a report includes a review of all provided documents,
testimony, reports, statements, audio and video and developing a sense of the
underlying facts as reported by all parties and witnesses without making credibility
determinations with respect to statements and testimony.” (Rec. Doc. 206-4 ¶ 17).
Throughout his report, Mr. Ryan utilizes the available video evidence and deposition
testimony to formulate his opinions. (Rec. Doc. 206-4 ¶¶ 330, 333). If Plaintiff believes
that Mr. Ryan is relying on EJLD Defendants’ version of events, Plaintiff is free to
challenge Mr. Ryan at trial. Sterusky v. Cooper, No. 22-cv-218, 2024 WL 4009668, at
*7 (W.D. Ky. Aug. 30, 2024) (rejecting a similar argument made by Plaintiff and
explaining that “[l]egal actions that go to trial contain contested issues of fact, and
Plaintiff’s assertion that Ryan has adopted [defendant]’s testimony is not grounds for
exclusion. Plaintiff will have the opportunity to cross-examine Ryan on the bases for
Case 2:22-cv-04587-CJB-EJD Document 248 Filed 11/21/25 Page 9 of 10

10
his opinions.”) The Court rejects Plaintiff’s argument at this stage of the litigation.
Therefore, the Court will not exclude Mr. Ryan’s opinions on those grounds.
CONCLUSION
Accordingly,
IT IS HEREBY ORDERED that the motion is GRANTED in part and
DENIED in part as follows.
Mr. Ryan may testify as an expert in this case, but he will not be able to provide
statements not appropriately couched in terms of applicable police policies and
procedures. The remainder of Mr. Ryan’s report and testimony is admissible.
New Orleans, Louisiana, this 21st day of November, 2025.
CARL J. BARBIER
UNITED STATES DISTRICT JUDGE
Case 2:22-cv-04587-CJB-EJD Document 248 Filed 11/21/25 Page 10 of 10