govinfo:USCOURTS-cand-3_21-cv-05435-4

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United States District Court 
Northern District of California 
 
 
 
UNITED STATES DISTRICT COURT 
NORTHERN DISTRICT OF CALIFORNIA 
 
MICHAEL MCCURTY, 
Plaintiff, 
v. 
 
H. MADSEN, et al., 
Defendants. 
 
Case No.  21-cv-05435-SI    
 
 
ORDER RE: DAUBERT MOTIONS 
Re: Dkt. Nos. 85, 86 
 
Plaintiff and defendants each filed one Daubert motion seeking to exclude expert testimony.  
Dkt. Nos. 85, 86.  The Court’s determination as to each motion is detailed below. 
 
BACKGROUND 
Plaintiff is a prisoner at the Correctional Training Facility (“CTF”) in Soledad, California.  
Dkt. No. 1 (“Compl.) at 1.1  On July 15, 2021, plaintiff filed this suit pro se and named the following 
CTF employees as defendants: Correctional Officer H. Madsen,  Correctional Officer Arlene 
Stephens, Warden Craig Koenig, and Does 1-3.  Compl.  The Court found plaintiff asserted a 
cognizable Eight Amendment sexual harassment claim.  Dkt. No. 4 (“Order of Service”) at 4.  But 
the Court found plaintiff’s claim of incitement to violence non- cognizable.  Id. at 4-5.  The Court 
dismissed defendants Does 1-3.  Dkt. No. 22 at 4.   
 In his complaint, plaintiff alleges that on August 10, 2019, defendants Madsen and Stephens 
conducted a search of plaintiff’s cell and a “clothed body search of Plaintiff.”  Compl. ¶ 4.  During 
the search, defendant Madsen ordered plaintiff to step out of the cell and then defendant Madsen 
pulled down plaintiff’s pants causing his “buttocks to be exposed to the approximately 40 to 60 
 
1 Unless otherwise noted, pin cites to Docket No. 1 refer to the ECF pagination. 
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other inmates in the wing’s dayroom, other inmates in their cells, and defendant Stephens.”  Id. ¶¶ 
5, 8.  After pulling down plaintiff’s pants, defendant Madsen grabbed plaintiff’s buttocks and 
grabbed and squeezed his genitalia.  Id. ¶¶ 13-14.  For the aforementioned events, defendant 
Stephens stood and watched.  Id. ¶¶ 9,12.  Additionally, plaintiff alleges defendant Warden Koenig 
has been aware of “staff sexual misconduct” since as early as 2018 and has failed to properly address 
it.  Id.  ¶¶ 24, 25. 
On February 17, 2026, this case was re -assigned to this Court.  Dkt. No. 94.  The pretrial 
conference is set for April 21, 2026, and trial is set to begin May 4, 2026.  Dkt. No. 97.  
 
LEGAL STANDARD 
Federal Rule of Evidence 702 permits the introduction of expert testimony only if “(a) the 
expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand 
the evidence or to determine a fact in issue; (b) the testimony is based on sufficient facts or data; (c) 
the testimony is the product of reliable principles and methods; and (d) the expert’s opinion reflects 
a reliable application of the principles and methods to the facts of the case.”  Fed. R. Evid. 702.  “To 
qualify as an expert, a witness must have ‘knowledge, skill, experience, training, or education’ 
relevant to such evidence or fact in issue.”  U.S. v. Chang, 207 F.3d 1169, 1172 (9th Cir. 2000) 
(citing Fed. R. Evid. 702).  Expert testimony is admissible “only if it is both relevant and reliable.”  
Kumho Tire Co., Ltd. v. Carmichael, 526 U.S. 137, 141 (1999). 
The proponent of the expert testimony has the burden of proving the proposed expert 
testimony is admissible.  Lust ex rel. Lust v. Merrell Dow Pharm., Inc., 89 F.3d 594, 598 (9th Cir. 
1996).  On December 1, 2023, Rule 702(d) was amended to “clarify and emphasize that expert 
testimony may not be admitted unless the proponent demonstrates to the court that it is more likely 
than not that the proffered testimony meets the admissibility requirements set forth in the rule.”  Fed. 
R. Evid. 702 (Adv. Comm. Note, 2023).  However, Rule 702 “should be applied with a ‘liberal 
thrust’ favoring admission.”  Messick v. Novartis Pharm. Corp., 747 F.3d 1193, 1196 (9th Cir. 2014) 
(citing Daubert v. Merrell Dow Phar ms., Inc., 509 U.S. 579, 588 (1993)).  “Shaky but admissible 
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evidence is to be attacked by cross examination, contrary evidence, and attention to the burden of 
proof, not exclusion.”  Primiano v. Cook, 598 F.3d 558, 564 (9th Cir. 2010).  
Rule 702 requires that the trial court act as a “gatekeeper” by “making a preliminary 
determination that the expert’s testimony is reliable.”  Elsayed Mukhtar v. Cal. State Univ., 
Hayward, 299 F.3d 1053, 1063 (9th Cir. 2002) (citations omitted); see Daubert , 509 U.S. at 597.  
The decision whether to admit or exclude expert testimony lies within the trial court’s discretion. 
See General Elec. Co. v. Joiner , 522 U.S. 136, 141- 42 (1997); United States v. Calderon- Segura, 
512 F.3d 1104, 1109 (9th Cir. 2008).  T he Ninth Circuit has acknowledged that Daubert “may be 
harder to apply when the expert testimony is ‘experience -based’ rather than ‘science-based,’” but 
an examination of reliability may be more important in considering “experience -based” opinion.  
United States v. Valencia-Lopez, 971 F.3d 891, 898 (9th Cir. 2020).  Additionally, Rule 702 “makes 
no relevant distinction between ‘scientific’ knowledge and ‘technical’ or ‘other specialized’ 
knowledge.”  Kumho Tire, 526 U.S. at 147. 
 
DISCUSSION 
I. Defendants’ Daubert Motion: Lonnell Goodall 
Plaintiff enlisted Lonnell Goodall to review and evaluate the prison’s investigation into 
plaintiff’s allegation of defendants’ sexual misconduct.  Mr. Goodall has over twenty-five years of 
law enforcement experience, including serving in two different detention and corrections facilities.  
Dkt No. 91-2 ¶¶ 3-4 (“Goodall Report”).  Mr. Goodall also worked for nine years in internal affairs 
where he conducted over 200 internal investigations into employee misconduct.  Id. ¶¶ 4, 8 -9.  
Defendants challenge Mr. Goodall’s report and offered testimony on several grounds.  Dkt. No. 85. 
First, defendants argue that Mr. Goodall does  not have “operational experience” at  the 
California Department of Corrections and Rehabilitation (“CDCR”) and is unable to testify to the 
quality of the prison’s investigation.  Dkt No. 85 at 3- 4.  Plaintiff responds  that there is no 
requirement that a witness work for a specific institution to be allowed to testify about the quality 
of that institution’s investigation.  Dkt. No. 91 at 3.  Further, plaintiff  argues Mr. Goodall has a 
plethora of experience conduc ting internal investigations.   Id. at 4.  The Court finds that Mr. 
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Goodall’s work conducting internal law enforcement investigations gives him  the requisite 
experience to testify about the quality of an internal investigation and that he does not need to have 
worked for CDCR to testify to the quality of their investigation. 
Second, defendants seek to exclude comments from Mr. Goodall that offer improper legal 
opinions.  Dkt. No. 85 at 5.  Specifically, defendants object to a line from Mr. Goodall’s where he 
states, “that the weight of the evidence supports the notion that Defendant Madsen did sexually 
assault Mr. McCurty.”  Id.; See Dkt. No. 91-2 at 17.  Plaintiff does not address this point in its brief.  
The Court agrees with defendants ’ objection and instructs Mr. Goodall not to make any legal 
conclusions including “that the weight of the evidence supports the notion that Defendant Madsen 
did sexually assault Mr. McCurty.”  See Dkt. No. 91-2 at 17. 
Third, defendants claim that Mr. Goodall’s opinions improperly rely on credibility 
determinations.  Dkt. No. 85 at 5- 8.  Defendants take issue with Mr. Goodall’s testimony that 
Lieutenant Landrum was biased in his investigation and that plaintiff’s allegations were 
corroborated and should be given weight.  Id. at 6-7.  Plaintiff argues that Mr. Goodall’s testimony 
is not based on credibility determinations, but instead rests on conclusions regarding inconsistent 
reports.  Dkt. No. 91 at 5-6.  The Court finds that Mr. Goodall can testify to the quality of the prison’s 
internal investigation and any inconsistencies therein but cannot weigh the evidence and assert 
which side’s account is more credible. 
Fourth, defendants seek to exclude any of Mr. Goodall’s testimony which is based on 
speculation.  Dkt. No. 85 at 8-9.  Specifically, defendants seek to exclude Mr. Goodall’s assertions 
that inmates do not tend to report incidents due to a “fear of retaliation,” as well as his conclusions 
that Lieutenant Landrum was biased in his investigation.  Id.  Plaintiff does not specifically defend 
these assertions made by Mr. Goodall.  The Court finds that although Mr. Goodall can testify to 
inconsistencies in the record, he cannot make conclusions regarding the state of mind of relevant 
witnesses.   
Fifth, defendants argue that if Goodall is permitted to testify the Court must limit him to only 
responding to hypothetical questions.  Dkt. No. 85 at 9.  Plaintiff does not specifically address this 
argument in his response.  Mr. Goodall can testify to the quality of the prison’s investigation in this 
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case, but regarding any discussion of use of force tactics such questioning must be limited to 
hypotheticals.  See Valtierra v. City of Los Angeles , 99 F. Supp. 3d 1190, 1198 (C.D. Cal. 2015)  
(limiting a police procedure expert’s testimony on use of force to “hypothetical questioning so as to 
avoid invading the province of the jury.”). 
As explained above, the motion to exclude testimony from Mr. Goodall is GRANTED in 
part and DENIED in part. 
 
II. Plaintiff’s Daubert Motion: John Diaz 
Defendants enlisted John Diaz  to review and evaluate the prison’s investigation into 
plaintiff’s allegation of defendants’ sexual misconduct.  Mr. Diaz worked for CDCR for over 
twenty-five years.  Dkt. No. 87- 3 at 18 ( “Diaz Report”).
2  For twenty -three of those years with 
CDCR, Mr. Diaz worked as a supervisor and master trainer where he trained correctional officers 
and conducted “policy compliance reviews.”  Id.  at 18-19.  Plaintiff challenges Mr. Diaz’s report 
and offered testimony on several grounds.  Dkt. No. 86. 
First, plaintiff argues that Mr. Diaz offers no specialized knowledge that will assist the jury.  
Dkt. No. 86 at 5-7.  Specifically, plaintiff argues Mr. Diaz’s experience as a prison operation expert 
does not relate to any disputed issue, Mr. Diaz’s opinions do not relate to a prison policy or 
operations issue, and his opinions are based on improper credibility determinations.  Id. at 5.  
Defendants argue that Mr. Diaz’s testimony is necessary so that the jury can understand the 
“institutional context” in which the defendant s’ alleged acts occurred.  Dkt. No. 90 at 4.  
Specifically, defendants argue Mr. Diaz’s testimony is needed for the jury to understand “CDCR’s 
search procedures and documentation requirements,” “prison gang dynamics,” and “inmate 
behavior patterns.”  Id. at 4-5.  The Court finds that Mr. Diaz is allowed to testify because his 
testimony may assist the jury in determining whether defendant s’ actions were appropriate within 
CDCR’s operational context.   
Second, plaintiff seeks to exclude comments from Mr. Diaz that intrude on the jury’s 
 
2 Unless otherwise noted, pin cites to Docket No. 87-3 refer to the ECF pagination. 
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function.  Dkt. No. 86 at 7- 8.  P laintiff argues Mr. Diaz engages in impermissible credibility 
determinations when he states “[n]o evidence has been provided to me that  would corroborate 
[McCurty’s] allegation partially or in its entirety.”  Id.  Defendants respond that Mr. Diaz analyzes 
the quality of the documentary record, does not opine on witness truthfulness, and that his testimony 
will be limited to hypotheticals .  Dkt. No. 90 at 5 -7.  The Court finds that Mr. Diaz can testify to 
inconsistencies throughout the entire documentary record and why those inconsistencies suggest 
that defendants were or were not justified in their investigative actions.  But Mr. Diaz is not 
permitted to conclude that some evidence should be credited over other pieces or to opine on whether 
or not there is enough evidence to “corroborate [McCurty’s] allegation partially or in its entirety.” 
Third, plaintiff argues that Mr. Diaz’s testimony will unfairly prejudice plaintiff, a convicted 
felon.  Dkt. No. 86 at 8- 9.  Defendants respond that the probative value of Mr. Diaz’s testimony 
regarding the institutional context, is not substantially outweighed by any prejudicial effect of the 
testimony.  Dkt. No. 90 at 7- 8.  Under Rule 403, courts “may exclude relevant evidence if its 
probative value is substantially outweighed by…unfair prejudice.”  Fed. R. Evid. 403.  Here,  the 
Court finds that the prejudicial effect of Mr. Diaz’s testimony does not outweigh the probative value 
of Mr. Diaz testifying to the institutional context of the prison.  Further, this Court has already 
prohibited Mr. Diaz from making explicit credibility determinations. 
Fourth, plaintiff argues that the Court should disqualify Mr. Diaz “because his opinions 
exhibit extraordinary bias and are therefore unduly prejudicial.”  Dkt. No. 86 at 9-10.  Specifically, 
plaintiff takes issue with Diaz’s comments during his deposition that he does not “know any female 
correctional officers…who would willingly do anything that was described in this type of 
allegation” and that there would be “zero tolerance” “by the black inmate population” “for any white 
female to conduct a clothed body search.”  Id.; see Dkt. No. 87-3 at 6, 11-12 (“Diaz Deposition”).  
Defendants respond that Mr. Diaz is not applying stereotypes but is instead “describing patterns he 
has personally observed” based on “27 years of professional experience investigating thousands of 
incidents at a maximum-security male prison.”  Dkt. No. 90 at 8- 9.  Although the Court finds that 
Mr. Diaz is allowed to testify, the Court orders that Mr. Diaz is not allowed to use  generalities to 
explain how he believes the specific alleged conduct in this case is more or less likely. 
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As explained above, the motion to exclude testimony from Mr. Diaz is GRANTED in part 
and DENIED in part. 
CO
NCLUSION 
The parties’ Daubert motions are resolved as follows: The motions to exclude the reports and 
offered testimony of experts Goodall and Diaz are DENIED in part and GRANTED in part, as explained 
above.   
I
T IS SO ORDERED. 
Dated: April 3, 2026 
______________________________________
 
SUSAN ILLSTON 
United States District Judge 
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