                     FOR PUBLICATION

   UNITED STATES COURT OF APPEALS
        FOR THE NINTH CIRCUIT


 C. DWAYNE GILMORE, AKA Cary D.                    No. 17-15636
 Gilmore,
               Plaintiff-Appellant,                  D.C. No.
                                                  1:12-cv-00925-
                      v.                               SAB

 C. LOCKARD, C/O; C. LOPEZ, C/O; J.
 HIGHTOWER, C/O,                                      OPINION
              Defendants-Appellees.

        Appeal from the United States District Court
            for the Eastern District of California
     Stanley Albert Boone, Magistrate Judge, Presiding

             Argued and Submitted June 13, 2019
                  San Francisco, California

                      Filed August 28, 2019

    Before: MARY M. SCHROEDER and MILAN D.
    SMITH, JR., Circuit Judges, and JED S. RAKOFF, *
                     District Judge.

             Opinion by Judge Milan D. Smith, Jr.


    *
      The Honorable Jed S. Rakoff, United States District Judge for the
Southern District of New York, sitting by designation.
2                     GILMORE V. LOCKARD

                          SUMMARY **


                      Prisoner Civil Rights

    The panel reversed the district court’s jury verdict in
favor of defendant prison officials and remanded for further
proceedings in an action brought by a California state
prisoner pursuant to 42 U.S.C. § 1983 alleging that
defendants used excessive force against him and delayed his
access to medical assistance.

    Plaintiff consented to the jurisdiction of a magistrate
judge pursuant to 28 U.S.C. § 636(c). Nearly two years later,
defendants declined consent, and the case was assigned to a
district court judge. Thereafter, the magistrate judge
originally assigned to this case retired, and another
magistrate judge took over the case to address pretrial
motions. Following an adverse ruling on a motion to
compel, plaintiff filed a motion to withdraw his consent to
magistrate judge jurisdiction. The magistrate judge denied
plaintiff’s motion, stating that, pursuant to 28 U.S.C.
§ 636(c)(4), a request to withdraw consent will be granted
only upon a showing of good cause or extraordinary
circumstances, and that disagreement with a ruling did not
amount to good cause. Defendants subsequently consented
to magistrate judge jurisdiction, almost four years after
plaintiff’s consent.

   The panel held that a party need not satisfy the good
cause or extraordinary circumstances standard provided in

    **
       This summary constitutes no part of the opinion of the court. It
has been prepared by court staff for the convenience of the reader.
                   GILMORE V. LOCKARD                        3

§ 636(c)(4) in order to withdraw magistrate judge consent
before all parties have consented. The panel held that
because the magistrate judge erroneously required such a
showing by plaintiff, and because under the circumstances
his motion to withdraw consent should have been granted,
the magistrate judge lacked jurisdiction to conduct the trial.

    While plaintiff’s case was pending, the Attorney General
notified him that one of the defendants had died, but did not
identify a personal representative for the defendant’s estate.
The district court, adopting the magistrate judge’s
recommendation, dismissed the deceased defendant from the
action, along with plaintiff’s Eighth Amendment deliberate
indifference claim. The district court held that additional
attempts to identify a representative would be futile due to
Federal Rule of Civil Procedure 25(a)’s 90-day filing
requirement.

    The panel held that the magistrate judge erred by placing
the burden on plaintiff to identify the deceased defendant’s
successor or personal representative. The panel concluded
that Rule 25(a)’s 90-day window was not triggered, and
therefore the panel reversed the dismissal of the deceased
defendant, and reversed the dismissal of plaintiff’s deliberate
indifference to medical needs claim.

    The panel stated that because it was reversing the jury
verdict and remanding for further proceedings based on the
magistrate judge’s lack of jurisdiction, it was not necessary
to consider plaintiff’s evidentiary challenges in detail.
However, for the guidance of the trial court on remand, the
panel noted that the probative value of defendants’ expert
testimony about gangs to which plaintiff had no connection
was minimal and was substantially outweighed by the
danger of unfair prejudice.
4                 GILMORE V. LOCKARD

                       COUNSEL

Douglas A, Smith (argued) and Maximillian Wolden Hirsch
(argued), Los Angeles, California, for Plaintiff-Appellant.

Martha P. Ehlenbach (argued), Deputy Attorney General;
Misha D. Igra, Supervising Deputy Attorney General;
Monica N. Anderson, Senior Assistant Attorney General;
Xavier Becerra, Attorney General; Office of the Attorney
General, Sacramento, California; for Defendants-Appellees.


                        OPINION

M. SMITH, Circuit Judge:

    Plaintiff Cary Dwayne Gilmore filed an action pursuant
to 42 U.S.C. § 1983, alleging civil rights violations by
various prison officials (together, Defendants) following an
incident at Kern Valley State Prison (Kern Valley). A jury
ultimately ruled against Gilmore, finding that Defendants
did not use excessive force during the alleged incident.

    We reverse on several grounds.

    FACTUAL AND PROCEDURAL BACKGROUND

I. Factual Background

    Gilmore alleged that on July 8, 2010, after an alarm
sounded due to a disturbance created by two non-party
inmates at Kern Valley, he was beginning to lie down—
“prone out”—when Defendant Chad Lockard shot him with
a sponge round in the right leg near his knee. Lockard then
directed Defendant Cesar Lopez to check on Gilmore, who
was on the ground after being shot. Gilmore claimed that
                   GILMORE V. LOCKARD                       5

Lopez then began to pepper spray him. Defendant John
Hightower also allegedly walked over and pepper sprayed
Gilmore, until both he and Lopez had emptied their pepper
spray cans. Afterwards, Defendant J.J. Torres handcuffed
Gilmore and forced him to walk despite his knee injury.
Gilmore alleged that Torres repeatedly forced him into
obstacles such as door frames and walls, breaking his glasses
and injuring his face. Torres purportedly laughed and said,
“You gotta watch where you’re going Gilmore!” Gilmore
claimed that Torres then made him sit on hot asphalt for
27 minutes while he awaited medical attention, exacerbating
the “burning” from the pepper spray. Finally, when Torres
agreed to decontaminate Gilmore, he forced Gilmore to
kneel while he sprayed him with water. Afterwards,
Gilmore received medical attention for the gunshot wound.

II. Procedural Background

    Gilmore filed this action pursuant to 42 U.S.C. § 1983,
alleging that Defendants used excessive force when
responding to the incident at Kern Valley, and subsequently
delayed his access to medical assistance. On March 2, 2017,
after trial, a jury found in favor of Defendants.

   A. Motion to Withdraw Consent to Magistrate
      Judge Jurisdiction

    On June 29, 2012, Gilmore consented to the jurisdiction
of a magistrate judge pursuant to 28 U.S.C. § 636(c). Nearly
two years later, on May 19, 2014, Defendants declined
consent, and the case was then assigned to District Judge
Lawrence J. O’Neill. The district court rejected Gilmore’s
objection to the reassignment, noting that “under § 636(c), if
all parties do not consent to Magistrate Judge jurisdiction, a
District Judge must be assigned as presiding judge.”
Thereafter, the magistrate judge originally assigned to this
6                 GILMORE V. LOCKARD

case retired, and Magistrate Judge Stanley A. Boone took
over the case, at this point in the case to address pretrial
motions.

   On October 19, 2015, following an adverse ruling on a
motion to compel, Gilmore filed a motion to withdraw his
consent to magistrate judge jurisdiction. The magistrate
judge stated that, pursuant to 28 U.S.C. § 636(c)(4), “a
request to withdraw consent will be granted only upon a
showing of good cause or extraordinary circumstances.”
Finding that Gilmore’s disagreement with his ruling—
Gilmore had suggested that the magistrate judge “ha[d]
shown partiality for defendants” when ruling on the
motion—did not amount to good cause, the magistrate judge
denied Gilmore’s motion.

    On September 1, 2016, over four years after Gilmore
consented to magistrate judge jurisdiction, Defendants
finally gave their consent to Magistrate Judge Boone
conducting all further proceedings. Pursuant to 28 U.S.C.
§ 636(c), the case was thereafter assigned to Magistrate
Judge Boone for all pretrial and trial proceedings.

    B. Motion to Substitute Defendant Torres

    On February 24, 2014, the Deputy Attorney General
(AG) representing Lopez and Hightower notified Gilmore
that Torres had died, but did not identify a personal
representative for Torres’s estate. The notice stated,
“Counsel for Defendant Torres is informed that the
Defendant has died.” Defendants now claim that the AG
sent the notice in error because the AG represented only
Lopez and Hightower at the time. On March 5, 2014,
Gilmore filed an “Opposition and Reply to Notice of
Defendant’s Death,” which the magistrate judge construed
as a motion to substitute parties. The magistrate judge
                   GILMORE V. LOCKARD                        7

denied this motion without prejudice, noting that “Plaintiff
. . . is responsible for identifying and finding J.J. Torres’
heirs or representatives.”

    Gilmore then filed a second substitution motion,
asserting that counsel for Torres—the AG, as stated in the
notice—was the representative of the estate, and requesting
that the Deputy AG assigned to the case be served with his
motion. The magistrate judge denied the motion, again
asserting that Gilmore was responsible for providing the
name and address of Torres’s heir or representative.
Gilmore then filed three additional substitution motions in
an attempt to provide information about Mrs. Elizabeth
Torres, Torres’s widow, whom Gilmore claimed was
Torres’s heir. After the magistrate judge allowed limited
discovery concerning the proper party to substitute, Gilmore
offered as proof two obituaries indicating that Torres was
survived by his wife, as well as copies of the white pages
indicating Mrs. Torres’s address. The magistrate judge
again denied Gilmore’s substitution motions because he
found the evidence insufficient.

    On November 20, 2014, Gilmore filed his final motion
to substitute parties, which included a declaration in addition
to the evidence previously submitted. Gilmore’s declaration
described a conversation between Gilmore’s then-fiancée,
Thalesha Denise Clay, and Mrs. Torres, wherein the latter
confirmed that she was the administrator of Torres’s estate.
In further briefing, Gilmore disclosed that Clay had posed as
a Department of Veterans Affairs employee in order to
solicit answers from Mrs. Torres. The magistrate judge
recommended denying Gilmore’s motion with prejudice,
noting that the declaration was inadmissible hearsay; that the
remaining evidence was insufficient to identify Mrs. Torres
as Torres’s legal representative; and that further attempts to
8                  GILMORE V. LOCKARD

identify a representative would be futile due to Federal Rule
of Civil Procedure 25(a)’s 90-day filing requirement.

    The district court adopted the magistrate judge’s
recommendation and dismissed Torres from the action,
along with Gilmore’s Eighth Amendment deliberate
indifference claim.

                        ANALYSIS

     Gilmore argues that the magistrate judge committed
several reversible errors over the course of the multi-year
litigation. We address each in turn.

I. Magistrate Judge Jurisdiction

    Gilmore first argues that the magistrate judge lacked
jurisdiction to conduct the trial pursuant to 28 U.S.C.
§ 636(c). Specifically, he contends that the magistrate judge
erred by erroneously requiring that Gilmore show “good
cause” in order to withdraw his consent.

     We review de novo whether a magistrate judge had
jurisdiction over a case. Irwin v. Mascott, 370 F.3d 924, 929
(9th Cir. 2004). “[T]he federal litigant has a personal right,
subject to exceptions in certain classes of cases, to demand
Article III adjudication of a civil suit.” Pacemaker
Diagnostic Clinic of Am., Inc. v. Instromedix, Inc., 725 F.2d
537, 541 (9th Cir. 1984). Like other fundamental rights, this
right can be waived: “When authorized under 28 U.S.C.
§ 636(c), a magistrate judge may, if all parties consent,
conduct a civil action or proceeding, including a jury . . .
trial.” Fed. R. Civ. P. 73(a).

    Here, Gilmore originally consented to magistrate judge
jurisdiction on June 29, 2012. Defendants then declined
                   GILMORE V. LOCKARD                        9

magistrate judge jurisdiction on May 19, 2014. Although
Defendants later consented to magistrate judge jurisdiction,
prior to that decision Gilmore sought to withdraw his
consent, “believ[ing] that Magistrate Judge Stanley A.
Boone ha[d] shown partiality for defendants and will not be
an impartial magistrate.” The magistrate judge denied
Gilmore’s motion, citing § 636(c)(4) and its standard for
withdrawing consent. That statute states, “The court may,
for good cause shown on its own motion, or under
extraordinary circumstances shown by any party, vacate a
reference of a civil matter to a magistrate judge under this
subsection.” 28 U.S.C. § 636(c)(4).

     Gilmore argues that because he sought to withdraw
consent before all parties consented to magistrate judge
jurisdiction, the civil matter was not yet properly before the
magistrate judge, and so the “good cause” standard under
§ 636(c) does not apply. Whether § 636(c)’s good cause
standard applies prior to consent by all parties is a matter of
first impression in our court.

    The text of the statute suggests that Gilmore is correct,
and that a showing of good cause is not required before all
parties have consented. Section 636(c) generally pertains to
matters where all parties have consented to magistrate judge
jurisdiction. Subsection (c)(1) applies only “[u]pon the
consent of the parties,” and subsections (c)(2) and (c)(3) only
relate to cases under subsection (c)(1). Id. § 636(c)(1)–(3).
It follows then that subsection (c)(4) similarly applies only
when the magistrate judge has jurisdiction over all
proceedings, “[u]pon the consent of the parties.” By
contrast, at the time the magistrate judge ruled on Gilmore’s
motion to withdraw, he only had authority pursuant to
§ 636(b), which applies where “a judge [] designate[s] a
magistrate judge to hear and determine any pretrial matter
10                 GILMORE V. LOCKARD

pending before the court.” Id. § 636(b)(1)(A). Section
636(b) does not have a good cause or extraordinary
circumstances requirement, and so Gilmore was not required
to make such a showing when he moved to withdraw his
consent.

    Defendants claim that the magistrate judge retained
jurisdiction pursuant to § 636(c) at the time of Gilmore’s
motion to withdraw, but this is inaccurate. A district court
in our circuit explained succinctly the key distinction that
applies in this case:

       There is a distinction between assignment of
       an action to a Magistrate Judge pursuant to
       28 U.S.C. § 636(b) and reassignment of an
       action to a Magistrate Judge pursuant to 28
       U.S.C. § 636(c) . . . . When an action is filed,
       it is assigned to a United States District Judge
       and a United States Magistrate Judge. If all
       the parties consent to Magistrate Judge
       jurisdiction pursuant to § 636(c), the action is
       reassigned by the United States District
       Judge assigned to the case to the Magistrate
       Judge assigned to the case, and the
       Magistrate Judge conducts all further
       proceeding[s], including trial. When plaintiff
       filled out the consent/decline form and
       checked the box marked “Consent,” he was
       consenting pursuant to section 636(c).
       However, [at that point] plaintiff’s consent
       did not result in reassignment of this action to
       a Magistrate Judge. Cases are reassigned to
       a Magistrate Judge only if all parties consent.
       If one or more parties decline Magistrate
       Judge jurisdiction, the District Judge will
                      GILMORE V. LOCKARD                            11

        resolve all dispositive matters and conduct
        the trial, if there is one.

Page v. California, No. 1:06-cv-01409 LJO DLB PC, 2008
WL 3976933, at *1 (E.D. Cal. Aug. 20, 2008). Gilmore filed
his motion to withdraw consent on October 19, 2015—after
Defendants denied consent, after the case was assigned to
District Judge Lawrence J. O’Neill, and before Defendants
later consented to magistrate judge jurisdiction. Therefore,
the magistrate judge did not have jurisdiction pursuant to
§ 636(c). 1

    We must necessarily consider the practical implications
of our holding, one of which was highlighted by one of our
sister circuits in Carter v. Sea Land Services, Inc., 816 F.2d
1018 (5th Cir. 1987). There, the Fifth Circuit stated:

        [N]othing in the statute or the legislative
        history [] requires continuing expressions of
        consent before a magistrate can exercise
        authority under a valid reference. Nor will
        we accept the slippery-slope invitation to
        read into the statute a rule that would allow a
        party to express conditional consent to a
        reference, thereby obtaining what amounts to
        a free shot at a favorable outcome or a veto of
        an unfavorable outcome. Any such rule
        would allow the party to hold the power of
        consent over the magistrate like a sword of
        Damocles, ready to strike the reference

    1
      Indeed, the fact that the magistrate judge submitted findings and
recommendations to dismiss Torres as a defendant demonstrates that he
did not have jurisdiction over all proceedings pursuant to § 636(c), but
only an assignment under § 636(b).
12                     GILMORE V. LOCKARD

         should the magistrate issue a ruling not quite
         to the party’s liking.

Id. at 1020–21. Allowing a party to withdraw consent
without utilizing the good cause standard could indeed allow
a litigant to “shop” between a magistrate and a district judge.
The facts of this case suggest that might have been precisely
what Gilmore sought to do when he filed his motion to
withdraw after receiving an unfavorable ruling.

    Importantly, however, Carter is distinguishable. There,
as in almost every case where a court reviews a ruling on a
motion to withdraw consent, 2 both parties had consented to
magistrate judge jurisdiction. Id. at 1020. The Carter court
worried about a litigant seeking to withdraw consent after
both parties had consented and the magistrate judge had
made determinative rulings pursuant to § 636(c). Here, by
contrast, Defendants had not yet consented, and the
magistrate judge had not made rulings outside of limited
pretrial motions as provided in § 636(b). The concern over
forum shopping between a magistrate judge and an Article


     2
       The cases upon which Defendants rely all involved circumstances
where all parties had consented. See Dixon v. Ylst, 990 F.2d 478, 480
(9th Cir. 1993); United States v. Neville, 985 F.2d 992, 999–1000 (9th
Cir. 1993). The only case supporting Defendants’ position is Espinoza
v. Diaz, No. 1:17-cv-00338-SAB (PC), 2018 WL 910520 (E.D. Cal. Feb.
14, 2018), aff’d on other grounds, 723 F. App’x 488 (9th Cir. 2018),
where, coincidentally, Magistrate Judge Boone denied a plaintiff’s
motion to withdraw consent for failure to show good cause. Id. at *1.
Importantly, the plaintiff in Diaz proceeded in front of an Article III
judge, since the defendants continued to decline consent. Id. at *2. Thus,
plaintiff never appealed Magistrate Judge Boone’s denial of his motion
to withdraw consent, and so the propriety of that ruling was never
considered.
                       GILMORE V. LOCKARD                             13

III judge is lessened if the magistrate judge can make only
nondispositive pretrial rulings. 3

     But if the good cause or extraordinary circumstances
standard is not required, then how should a court adjudicate
a motion to withdraw consent in such cases? We conclude
that this is a decision best left to the district court’s
discretion, and we note that the majority of courts have
allowed such withdrawal in similar cases. See, e.g., Osotonu
v. Ringler, No. CIV S-10-2964 DAD P, 2011 WL 1047730,
at *5 (E.D. Cal. Mar. 18, 2011); Bowman v. Schwarzenegger,
No. CIV S-07-2164 FCD KJM P, 2009 WL 799274, at *1
(E.D. Cal. Mar. 23, 2009), aff’d on other grounds, 334 F.
App’x 850 (9th Cir. 2009)) (“Because this action has not yet
been reassigned to the [magistrate judge] for all purposes
including trial, plaintiff may withdraw his consent without
demonstrating good cause or extraordinary circumstances”);
Page, 2008 WL 3976933, at *2. We find these cases
instructive. Gilmore, a pro se plaintiff, filed a timely motion
to withdraw consent. There was no possible prejudice to
Defendants at the time Gilmore sought withdrawal, nor was
it inconvenient to the district court since the case had already
been assigned to District Judge O’Neill. Cf. United States v.
Mortensen, 860 F.2d 948, 950 (9th Cir. 1988) (holding, in
the context of a misdemeanor trial before a magistrate judge
pursuant to 18 U.S.C. § 3401(b), that “a withdrawal motion
is timely when granting the motion would not unduly
interfere with or delay the proceedings.”). Gilmore filed the

    3
       Moreover, Defendants can scarcely complain about Gilmore’s
judge-shopping, since Defendants sought to do the very same thing.
When at last they consented to magistrate judge jurisdiction, they
expressly limited that consent to Magistrate Judge Boone and purported
to “reserve the right to consent or decline to consent to any subsequently
assigned magistrate judge.”
14                 GILMORE V. LOCKARD

motion in response to an unfavorable pretrial ruling, but this
alone does not compel a finding that Gilmore’s consent is
irrevocable for all later dispositive rulings.

    In summary, a party need not satisfy the good cause or
extraordinary circumstances standard provided in
§ 636(c)(4) in order to withdraw magistrate judge consent
before all parties have consented. Because the magistrate
judge erroneously required such a showing by Gilmore, and
because under the circumstances his motion to withdraw
consent should have been granted, we conclude that the
magistrate judge lacked jurisdiction to conduct the trial.

II. Substitution of Parties

    The magistrate judge denied Gilmore’s repeated motions
to substitute Defendant Torres after his death, and dismissed
Gilmore’s deliberate indifference claim against Torres,
noting that it would have been futile since the 90-day period
to substitute under Rule 25(a)(1) had passed.

    “The proper interpretation of Rule 25(a) is a question of
law that we review de novo.” Barlow v. Ground, 39 F.3d
231, 233 (9th Cir. 1994). “Factual findings relevant to the
application of Rule 25(a) are reviewed for clear error.” Id.
Gilmore first argues that the notification of death was not
properly served upon Torres’s estate and, therefore, that
Rule 25(a)(1)’s 90-day window was never triggered.
Second, Gilmore contends that the magistrate judge
impermissibly placed the burden on him, an incarcerated pro
se plaintiff, to provide precise details of Torres’s estate.

    Before addressing Gilmore’s arguments, Defendants
suggest that Rule 25(a) has no application here because
personal jurisdiction was never established over Torres, who
died before service.       Defendants identify a largely
                   GILMORE V. LOCKARD                       15

unanswered question: whether substitution is available if a
party dies after the suit was filed but before being served
with process.

     The purpose behind Rule 25(a) suggests that substitution
remains available after filing and prior to service. Rule 25(a)
seeks “to inform all interested persons of [a party’s] death so
that they may take appropriate action.” Id. at 233 (quoting
3B Moore’s Federal Practice ¶ 25.06[2] (2d ed. 1991)).
Although service of summons must be completed before a
federal court may exercise personal jurisdiction over a party,
Omni Capital International, Ltd. v. Rudolf Wolff & Co.,
484 U.S. 97, 104 (1987), service after substitution would
still preserve a party’s rights and claims, while ensuring that
a court has personal jurisdiction over the new, proper party.
See 7C Charles Alan Wright & Arthur R. Miller, Federal
Practice and Procedure § 1951 (3d ed. 2007) (“If an action
was commenced by the filing of a complaint but a party
named in the complaint dies . . . before being served with
process, substitution is available, but, as in any instance of
substitution, process must be served on the new party to
acquire in personam jurisdiction.”).

    Indeed, the Supreme Court inferred as much more than a
century ago, finding “no reason why the representative of a
deceased party should not be brought in by the same
procedure, whether the death of a party occur before or after
service,” when interpreting a similar California state
procedural rule. Ex parte Connaway, 178 U.S. 421, 431
(1900). Although our court has not yet extended Connaway
to the federal rule, we observe that the decisions of various
out-of-circuit courts imply that such an application is proper.
See, e.g., Ransom v. Brennan, 437 F.2d 513, 518 (5th Cir.
1971) (“[I]f no in personam jurisdiction had been acquired
over the original party, then the substitution of a new party
16                    GILMORE V. LOCKARD

under Rule 25(a)(1) . . . places the substituted party in the
same position as the original party, i.e., a party to the action,
but one who must be still served with process to secure in
personam jurisdiction over him.”) (quoting Bertsch v.
Canterbury, 18 F.R.D. 23, 27 (S.D. Cal. 1955)); Lummis v.
Eighth Jud. Dist. Ct., 576 P.2d 272, 272–73 (Nev. 1978)
(“Petitioners construe [Nevada’s analogous Rule 25(a)] to
require the deceased to be a ‘party’ jurisdictionally before
the court. . . . Such a restrictive interpretation of the
identical federal rule has been previously rejected.”). 4
Relying on the purpose of Rule 25(a)(1), and finding these
prior cases persuasive, we conclude that Rule 25 applies in
this case, and proceed to the merits of Gilmore’s appeal.

    Gilmore challenges whether the 90-day substitution
window was triggered when he received notice from the AG
of Torres’s death, and whether it was his burden to identify
Torres’s personal representative or successor. Rule 25(a)
states:

         If a party dies and the claim is not
         extinguished, the court may order
         substitution of the proper party. A motion for
         substitution may be made by any party or by

     4
       Despite Defendants’ urging, we find Goldlawr, Inc. v. Shubert,
175 F. Supp. 793 (S.D.N.Y. 1959), unpersuasive. There, the court
expressed doubt that “Rule 25(a)(1) . . . may be invoked to authorize
substitution of the executors for a defendant who neither appeared nor
was served with process.” Id. at 797. But it did so in the context of
whether personal jurisdiction over the original defendant even existed in
the first place. Id. at 795–97. This context distinguishes Goldlawr from
the case before us. We further find Mizukami v. Buras, 419 F.2d 1319,
1320 (5th Cir. 1969), inapposite since that suit was filed after the
defendant’s death, and Rule 25(a) presupposes that the deceased was
already a party in the action prior to death.
                    GILMORE V. LOCKARD                       17

       the decedent’s successor or representative. If
       the motion is not made within 90 days after
       service of a statement noting the death, the
       action by or against the decedent must be
       dismissed.

       ...

       A motion to substitute, together with a notice
       of hearing, must be served on the parties as
       provided in Rule 5 and on nonparties as
       provided in Rule 4. A statement noting death
       must be served in the same manner.

Fed. R. Civ. P. 25(a)(1), (3) (emphases added). Rule 25(a)
thus “requires two affirmative steps in order to trigger the
running of the 90 day period. First, a party must formally
suggest the death of the party upon the record. Second, the
suggesting party must serve other parties and nonparty
successors or representatives of the deceased with a
suggestion of death in the same manner as required for
service of the motion to substitute.” Barlow, 39 F.3d at 233
(emphasis added) (citations omitted). In Barlow, the
defendants filed a suggestion of death after the plaintiff died,
but did not serve it on the plaintiff’s easily ascertainable
estate. Id. at 232. We held that the suggestion of death did
not trigger the 90-day window of Rule 25(a)(1), since the
rule requires that the “statement noting death must be served
in the same manner” as the motion to substitute—“on the
parties . . . and on nonparties.” Fed. R. Civ. P. 25(a)(1), (3).

   In Barlow, we did not reach the question of whether “the
suggestion of death [must] be served upon the nonparty
successors or representatives of the estate when the
appropriate persons could not be ascertained at the time the
18                 GILMORE V. LOCKARD

suggestion of death was made.” 39 F.3d at 234. Here, both
parties appear to agree that the successors or representatives
of Torres’s estate were not easily ascertainable. But
although Barlow did not answer this key question, other
circuits have suggested that nonparty successors or
representatives of the deceased party must be personally
served—or, at a minimum, identified—in order to trigger the
90-day period. See Fariss v. Lynchburg Foundry, 769 F.2d
958, 962 (4th Cir. 1985) (“Rule 25(a)(1) directs that both
parties and appropriate nonparties be served with the
suggestion of death to commence the 90-day substitution
period, for the rule seeks ‘to assure the parties to the action
and other concerned persons of notice of the death so that
they may take appropriate action to make substitution for the
deceased party.’”) (quoting 3B J. Moore & J. Kennedy,
Moore’s Federal Practice ¶ 25.06 (2d ed. 1982)); Rende v.
Kay, 415 F.2d 983, 985–86 (D.C. Cir. 1969) (“[T]he Rule,
as amended, cannot fairly be construed . . . to make
[decedent’s counsel’s] suggestion of death operative to
trigger the 90-day period even though he was neither a
successor nor representative of the deceased, and gave no
indication of what person was available to be named in
substitution as a representative of the deceased. [Such a]
construction would open the door to a tactical maneuver to
place upon the plaintiff the burden of locating the
representative of the estate within 90 days.” (footnote
omitted)); but see Unicorn Tales, Inc. v. Banerjee, 138 F.3d
467, 470 (2d Cir. 1998) (“The rule does not require that the
statement identify the successor or legal representative; it
merely requires that the statement of death be served on the
involved parties.”).

   In light of Rule 25(a)’s function, these cases attempted,
with varying results, to balance the importance of notice to
both parties and nonparties—which ensures that rights and
                      GILMORE V. LOCKARD                             19

causes of action are protected—with the burden of providing
such notice. In Barlow and Fariss, the successors or
representatives were easily ascertainable when the
respective suggestions of death were provided, and so the
courts found it appropriate to require such notice in order to
trigger the 90-day period. In Rende, the D.C. Circuit was
particularly concerned with placing the burden on a plaintiff
to identify the defendant’s successor or representative after
defendant’s counsel filed a suggestion of death. The D.C.
Circuit ultimately held that the suggestion of death must
identify the representative or successor before the 90-day
period is triggered. 415 F.2d at 985–86. Finally, in Unicorn
Tales, the Second Circuit disagreed with the D.C. Circuit and
found a suggestion of death sufficient to trigger the 90-day
window, even if no successor or representative was
identified, because Rule 6(b) allows time extensions for a
party to discover such individuals. 138 F.3d at 470.

    Finding Rende to be better reasoned, we hold that the
AG’s notice of death did not trigger the 90-day window. The
AG neither served notice to any nonparties, nor identified
such nonparties. Either circumstance would have put
Gilmore on notice as to Torres’s successor or personal
representative, information that he ultimately struggled to
obtain despite use of limited discovery and repeated
motions. 5 Whether or not the AG was actually Torres’s
counsel, she was significantly better positioned than
Gilmore to ascertain Torres’s successor since Defendants
Lopez and Hightower were indisputably her clients, and
given her existing relationship with the California
Department of Corrections and Rehabilitation (CDCR).
Shifting the burden to Gilmore to identify Torres’s successor

    5
      These repeated motions are a fairly clear indication that Rule 6(b)
extensions would not have assisted Gilmore in obtaining the information.
20                  GILMORE V. LOCKARD

or representative would defeat the purpose of Rule 25(a): to
preserve parties’ rights and causes of action when a party
dies. As the D.C. Circuit correctly observed in Rende, this
purpose would not be served by allowing Defendants to
place Gilmore at a tactical disadvantage, struggling to
identify Torres’s successors or personal representatives
within the 90-day deadline.

    Furthermore, nothing in Barlow suggests that where the
party filing the suggestion of death has not yet confirmed the
proper party for substitution, the burden of finding and
serving the substituted party should necessarily shift to the
other party. Instead, Barlow is better understood as
interpreting the 90-day rule judiciously: where a party files
a suggestion of death, it must do so in a manner that puts all
interested parties and nonparties on notice of their claims in
order to trigger the 90-day window. In that case, we required
defense counsel to serve plaintiff’s easily identifiable estate.
Here, we require, at a minimum, identification of Torres’s
successor or personal representative by Defendants, given
that they were much better suited than Gilmore to identify
the proper parties.

    Accordingly, because we hold that the magistrate judge
erred by placing the burden on Gilmore to identify Torres’s
successor or personal representative, we conclude that Rule
25(a)’s 90-day window was not triggered. We therefore
reverse dismissal of Torres as a defendant, and we reverse
the dismissal of Gilmore’s deliberate indifference claim.

    Defendants argue that substitution of Mrs. Torres at this
stage, if she is indeed the proper party, would be futile due
to the statute of limitations, as well as unduly burdensome.
But substitution would not be futile.             Defendants
misunderstand the effect of a Rule 25(a) substitution—Mrs.
Torres would not be a “new” party. Instead, the claim
                    GILMORE V. LOCKARD                       21

against Torres would survive because it was timely filed
before his death, and thus would relate back to the date of
the suit’s filing. See Flores v. City of Westminster, 873 F.3d
739, 761 (9th Cir. 2017). Defendants’ argument that
substitution would be unduly burdensome might be
persuasive, but it is not one that we are able to adjudicate. It
is instead a matter for the district court to consider on
remand.

III.    Expert Testimonies

    Because we reverse the jury verdict and remand for
further proceedings based on the magistrate judge’s lack of
jurisdiction, we need not consider Gilmore’s evidentiary
challenges in detail. However, “for the guidance of the trial
court on remand,” United States v. Mayans, 17 F.3d 1174,
1184 (9th Cir. 1994), we note that Officer Jalani Hunter was
permitted to offer testimony whose “probative value is
substantially outweighed by [the] danger of . . . unfair
prejudice.” Fed. R. Evid. 403. While Hunter’s testimony
about Gilmore’s alleged gang affiliation was largely
unobjectionable, his testimony about gangs to which
Gilmore had no connection whatsoever—including
organizations such as the Aryan Brotherhood and the
Mexican Mafia which have historic and public notoriety—
was of “marginal, if any, probative value.” Estate of Diaz v.
City of Anaheim, 840 F.3d 592, 603 (9th Cir. 2016). Still
more inflammatory was Hunter’s statement to the jury that
“the local streets that you guys live on, these hits that are
murders or whatever that’s taking place out on the street . . .
[are] taking place because of members housed in the
[CDCR].” Testimony of unrelated gang activity outside the
prison walls provided no useful information in this case
involving an altercation within prison walls. Given that
“[o]ur cases make it clear that evidence relating to gang
22                GILMORE V. LOCKARD

involvement will almost always be prejudicial,” Kennedy v.
Lockyer, 379 F.3d 1041, 1055 (9th Cir. 2004), the minimal
probative value of Hunter’s testimony is easily outweighed
by the tremendous risk of unfair prejudice to Gilmore and so
it should be excluded if the case is retried.

                     CONCLUSION

    We reverse the jury verdict, finding that the magistrate
judge did not have jurisdiction over trial proceedings
pursuant to § 636(c). We further reverse dismissal of Torres
as a Defendant, finding the 90-day window under Rule 25(a)
was never triggered, and we reverse the dismissal of
Gilmore’s deliberate indifference claim. We remand for
further proceedings consistent with this opinion.

     REVERSED AND REMANDED.
