                                       PRECEDENTIAL

      UNITED STATES COURT OF APPEALS
           FOR THE THIRD CIRCUIT
                   ______

                     No. 19-1823
                       ______

            CRYSTAL DAWN WEIMER

                          v.

    COUNTY OF FAYETTE, PENNSYLVANIA;
 OFFICE OF THE FAYETTE COUNTY OF DISTRICT
                 ATTORNEY;
  NANCY D. VERNON, in her official and individual
                  capacities;
  RONALD HAGGERTY, JR.; THOMAS CESARIO;
             THOMAS W. PATTON;
BEVERLY ASHTON, in their individual capacities; CITY
             OF CONNELLSVILLE


            County of Fayette; Nancy Vernon,
                                     Appellants
                       ______

    On Appeal from the United States District Court
       for the Western District of Pennsylvania
              (D. C. No. 2-17-cv-01265)
    Magistrate Judge: Honorable Maureen P. Kelly
                       ______
               Argued April 22, 2020
  Before: HARDIMAN, RENDELL and FISHER, Circuit
                     Judges.

                  (Filed: August 25, 2020)

Marie M. Jones [ARGUED]
Maria N. Pipak
Michael R. Lettrich
JonesPassodelis
707 Grant Street
Gulf Tower, Suite 3410
Pittsburgh, PA 15219
       Counsel for Appellants

Joseph E. Culleiton [ARGUED]
Blank Rome
501 Grant Street, Suite 850
Pittsburgh, PA 15219
       Counsel for Appellee

                            ______

                 OPINION OF THE COURT
                         ______

FISHER, Circuit Judge.
        Crystal Dawn Weimer spent more than eleven years in
prison for murder. After her convictions were vacated, all
charges against her were dismissed with prejudice. Weimer
then filed suit under 42 U.S.C. § 1983, alleging that the County
of Fayette, Pennsylvania; its former District Attorney, Nancy




                                2
Vernon; the City of Connellsville; and several city and state
police officers violated her rights under the U.S. Constitution
and Pennsylvania law. In this interlocutory appeal, we address
only a narrow sliver of this sweeping case: whether absolute
immunity or, where raised, qualified immunity shields District
Attorney Vernon from proceeding to discovery on certain of
Weimer’s claims. 1
       After assuring ourselves of our jurisdiction, we address
each immunity argument in turn. We conclude that, aside from
Vernon’s approval of the criminal complaint, because Weimer
alleges Vernon engaged in investigatory conduct, absolute
immunity does not protect Vernon from suit. However, we also
hold that Vernon is entitled to qualified immunity as to
Weimer’s failure to intervene claim and as to Vernon’s alleged
conduct in directing officers to investigate bite-mark evidence.
Thus, we will affirm in part, reverse in part, and remand for
further proceedings.
                                I
       In reviewing a district court’s “rulings on Federal Rule
of Civil Procedure 12(b)(6) motions to dismiss, our recitation

1
  As we explain below, our jurisdiction is premised on the
interlocutory appealability of a denial of immunity. We may
not, and do not, address issues that are unrelated to immunity.
At oral argument, counsel for Fayette County and Vernon
conceded that we lack jurisdiction to review the County’s
appeal because a county “may not raise absolute immunity as
a defense to a claim of municipal liability.” See Fogle v. Sokol,
957 F.3d 148, 156 (3d Cir. 2020) (citing Owen v. City of
Independence, 445 U.S. 622, 638 (1980)). For the same reason,
counsel also conceded that we lack jurisdiction to review
Vernon’s challenge to Weimer’s supervisory liability claim.




                               3
of the facts is limited to” the plaintiff’s well-pleaded
allegations. Odd v. Malone, 538 F.3d 202, 205 (3d Cir. 2008).
“We accept those facts as true and draw all reasonable
inferences” in her favor. Id.
A. The Initial Investigation into Curtis Haith’s Murder
        In the early morning hours of January 27, 2001,
members of the Connellsville Police Department arrived at
Curtis Haith’s apartment to find Haith, who had been beaten
and shot in the face, lying dead outside on the sidewalk. At
officers’ request, Vernon also came to Haith’s apartment to
participate in and help direct the investigation.
        During their initial search of the crime scene, officers
recovered DNA samples and found a significant amount of
drug-related evidence inside Haith’s apartment. From speaking
with Haith’s neighbors and friends, police learned that he had
attended parties and had hosted a dozen or more people in his
apartment on the evening of January 26 and into the morning
of January 27.
        Officers soon began interviewing people who had
attended these parties, including Weimer. When officers
arrived at her house, Weimer was still dressed in the clothes
she had been wearing the night before. She had minor injuries
to her face and foot, and officers observed what looked like
mud and blood on her clothes. Weimer told officers that she,
Haith, and others had attended a party the night before and that
she had given Haith a ride from that party and dropped him off
at another party. She then spent the rest of the night at the
housing community where her mother and sisters lived. Her
cousin, sisters, and then-boyfriend Michael Gibson confirmed
her story. Weimer and Gibson also told officers that Weimer
injured her foot when they were “horseplaying” a few days
earlier. App. 87 ¶ 31. And Weimer said that the blood on her




                               4
shirt and the injury to her eye were caused by a fight with
Gibson. DNA testing later confirmed that the blood on
Weimer’s clothes belonged to Gibson, and none of the DNA
samples collected from the crime scene matched Weimer—in
fact, the samples suggested a male DNA profile.
B. Weimer Is Implicated
       In October 2002—over twenty months after the
murder—Thomas Beal, whom Weimer had dated before
Gibson, told police that Weimer and Gibson killed Haith.
According to Beal, Weimer had told him that the blood on her
clothes belonged to Haith (which, based on the DNA testing,
could not have been correct) and that she and Gibson shot
Haith.
       Around the same time, the Pennsylvania State Police
Cold Case Squad began to assist with the investigation. When
reviewing Haith’s autopsy photos, a state investigator saw
what she believed to be a bite mark on Haith’s hand. A Fayette
County dentist analyzed the injury. The dentist first concluded
that Gibson bit Haith, but after examining teeth impressions for
Weimer, she reported she could not identify which set of teeth
caused the mark.
       A bite-mark expert then reviewed Beal’s statement,
photos of the injury to Haith’s hand, and teeth impressions
from Gibson and Weimer. He concluded the bite mark matched
Weimer. Later in the investigation, questions arose as to the
timing of the bite mark and whether it could have occurred
hours or days before the murder. Vernon directed officers to
investigate the timing issue, and the expert was asked to update
his opinion. Without reviewing additional evidence, he
determined the bite occurred seven to ten minutes before
Haith’s death.
       After securing the bite-mark evidence, investigators




                               5
again spoke with Beal. Although he had previously claimed
that Weimer had told him that she and Gibson had killed Haith,
he now claimed “a black man named Lonnie” participated in
the murder. App. 92 ¶ 47. Investigation into this new story,
conducted at the direction of the police and Vernon, revealed
that “Lonnie” was incarcerated at the time of Haith’s murder.
Despite these puzzling changes to his story, Beal remained a
key witness.
       In August 2003—now over two and a half years since
the murder—Conrad Blair contacted police from prison and
said that a fellow inmate, Joseph Stenger, had confessed that
he was involved in Haith’s murder. Vernon and a Connellsville
police officer interviewed Blair who told them that Stenger,
Weimer, and Beal killed Haith. Blair also gave the interviewers
a statement he claimed Stenger had written. The written
statement, however, diverged from Blair’s account of
Stenger’s supposed confession—instead of claiming Stenger
was involved in the murder, the written statement said he
merely helped dispose of evidence in a pond.
       Based on this interview and the written statement,
Vernon assisted police in assembling a dive team to search the
pond. Vernon and several officers also met with Stenger’s
attorney, who denied that his client wrote the statement.
C. Proceedings Against Weimer
       In late December 2003, despite the conflicting
statements from Beal, Blair, and Stenger, officers prepared a
criminal complaint charging Weimer with Haith’s murder,
which Vernon approved. In January 2004—three years after
Haith’s death—Weimer was arrested.
       The case against Weimer fell apart almost immediately.
During a preliminary hearing, the Commonwealth called Beal
as a fact witness. While on the stand, Beal recanted his




                              6
previous statements implicating Weimer in Haith’s murder.
Instead, he testified that an officer “kind of like coaxed me
along on how to do it.” App. 94 ¶ 57. Following Beal’s
revelation, the judge dismissed the charges, and Weimer was
released.
        Nevertheless, investigators continued to focus their
efforts on Weimer. In July 2004, Stenger told police he would
implicate Weimer in exchange for a lighter sentence for his
unrelated convictions. Based on Stenger’s new statement,
officers again arrested and charged Weimer with Haith’s
murder.
        Eventually, Weimer was brought to trial in Fayette
County. On April 7, 2006, a jury convicted her of third-degree
murder and conspiracy to commit murder. She was sentenced
to fifteen to thirty years in prison.
D. Weimer Is Exonerated
       On October 1, 2015, a judge vacated Weimer’s
convictions and granted her request for a new trial. Weimer
alleges that, at this point, the police officers and Vernon
“continued to act in concert to cover up and suppress the
wrongful actions that led to . . . Weimer’s wrongful
convictions” and worked to “re-prosecute[] [her] for . . . [the]
murder.” App. 100–01 ¶ 86.
        During Weimer’s postconviction relief and 2016
pretrial proceedings, a great deal of exculpatory evidence came
to light. For example, Stenger recanted his prior stories,
conceding he knew nothing about Haith’s murder and that
police had walked him through his testimony. The bite-mark
expert also disavowed his trial testimony, stating that his
opinion that the bite mark was Weimer’s was based on “junk
science.” App. 102 ¶ 94. In addition, Weimer’s counsel
discovered letters in Vernon’s files from several jailhouse




                               7
informants. Although the informants had testified at trial that
they were not receiving deals in exchange for their testimony
against Weimer, the letters revealed that they had indeed asked
for deals and may have received them. Finally, an expert
reviewed Haith’s autopsy report and photos of Weimer’s
injuries on the morning of Haith’s murder. He concluded
Weimer’s injuries were consistent with her story that she and
Gibson had been “horseplaying” a few days before the murder.
App. 103 ¶ 95. On June 27, 2016, the charges against Weimer
were “dropped with prejudice.” App. 103 ¶ 96.
E. Weimer’s Civil Rights Case
       In September 2017, Weimer filed a civil rights suit in
the District Court, naming as defendants Fayette County, the
Office of the Fayette County District Attorney, the City of
Connellsville, several Connellsville police officers, one
Pennsylvania State Police officer, and Vernon.
         As relevant to this appeal, Weimer’s First Amended
Complaint alleged that Vernon maliciously prosecuted her in
violation of her Fourth and Fourteenth Amendment rights,
conspired with police to violate her civil rights, and failed to
intervene to prevent officers from violating her constitutional
rights. 2 Vernon moved to dismiss, arguing that Weimer failed
to state claims for relief and, in any event, that she is entitled

2
  Weimer also asserted claims against Vernon for deprivation
of liberty without due process in violation of the Fourteenth
Amendment and malicious prosecution under Pennsylvania
law. The District Court dismissed both claims with prejudice,
and those rulings are not at issue in this appeal. Further, as
mentioned above, Vernon conceded that we lack jurisdiction
to review her challenge to Weimer’s supervisory liability
claim, and, therefore, we do not discuss that claim here.




                                8
to absolute immunity. Vernon also argued that, if the District
Court determined that Weimer pleaded valid claims and
absolute immunity was not available, she was entitled to
qualified immunity regarding the failure to intervene claim and
for allegedly directing police to investigate the timing of the
bite mark.
       On September 14, 2018, the District Court issued an
opinion granting the motion in part and denying it in part. See
Weimer v. County of Fayette (Weimer I), No. 17-1265, 2018
WL 4404049, at *16–17 (W.D. Pa. Sept. 14, 2018). First,
noting that a prosecutor enjoys absolute immunity when she
functions as an advocate, the District Court dismissed
Weimer’s claims with prejudice to the extent they were
premised upon Vernon’s alleged prosecutorial misconduct. 3
The District Court dismissed the claims without prejudice,
however, to the extent they were premised on Vernon’s
investigatory acts. In doing so, the Court granted Weimer leave
to amend her complaint to allege specific investigatory
misconduct by Vernon. Finally, the Court denied the motion to
dismiss the malicious prosecution claim only to the extent the
claim was premised on Vernon’s investigation into the timing
of the bite mark. The record, the Court explained, would have
to be “further developed as it relates to the bite mark and
Vernon’s conduct concerning the [bite-mark] investigation . . .
before it c[ould] be determined whether she is entitled to
qualified immunity on this issue.” Id. at *9.

3
  Specifically, the Court held that Vernon was entitled to
absolute immunity for prosecuting Weimer using false
statements and bite-mark evidence, failing to disclose evidence
to defense counsel, allowing or encouraging witnesses to
testify falsely, and making misleading statements during
closing arguments. Weimer I, 2018 WL 4404049, at *9 n.3.




                              9
       Following the issuance of the September 2018 order,
Weimer filed a Second Amended Complaint. The new
complaint also asserted malicious prosecution, civil rights
conspiracy, and failure to intervene claims against Vernon, and
Weimer added additional factual allegations to support these
claims. Vernon again moved to dismiss, arguing that Weimer
failed to plead Vernon’s involvement in the police
investigation to support the claims the District Court had
dismissed without prejudice. Vernon also argued that if
Weimer’s Second Amended Complaint adequately stated a
failure to intervene claim against her, it should be barred by
qualified immunity.
        On April 5, 2019, the District Court denied the second
motion to dismiss the civil rights conspiracy and failure to
intervene claims. 4 Weimer v. County of Fayette (Weimer II),
No. 17-1265, 2019 WL 1509664 (W.D. Pa. Apr. 5, 2019).
First, it held that Weimer stated a claim for civil rights
conspiracy because the Second Amended Complaint
sufficiently alleged Vernon’s involvement in the police
investigation and her awareness of conflicting evidence
throughout the investigation. Second, the Court held that
Weimer pleaded facts to support a failure to intervene claim
against Vernon and that Vernon was not entitled to qualified
immunity on this claim.
        Vernon now appeals aspects of both the September


4
  The District Court did not address the malicious prosecution
claim in the April 2019 order. As we explain in further detail
below, the Court’s failure to address whether the newly
pleaded allegations in the Second Amended Complaint could
also serve as factual bases for the malicious prosecution claim
seems to us an oversight.




                              10
2018 and April 2019 orders.
                               II
        Before turning to the merits, we must address an
antecedent challenge to our jurisdiction. See Montanez v.
Thompson, 603 F.3d 243, 248 (3d Cir. 2010) (“We necessarily
exercise de novo review over an argument alleging a lack of
appellate jurisdiction.”). The District Court had subject-matter
jurisdiction pursuant to 28 U.S.C. §§ 1331 and 1343. Weimer
argues that we lack appellate jurisdiction under 28 U.S.C. §
1291 because neither of the District Court’s orders are
reviewable under the collateral order doctrine. According to
Weimer, the District Court did not rule on Vernon’s
entitlement to absolute immunity in the April 2019 order, nor
did the determinations in that order turn on issues of law. The
rulings in the September 2018 order are not properly before us,
Weimer argues, because Vernon failed to appeal any adverse
determinations in that order within thirty days as required by
Federal Rule of Appellate Procedure 4(a). As we explain
below, we hold that we may properly exercise jurisdiction over
all issues Vernon raises on appeal.
       We have jurisdiction to review “appeals from all final
decisions of the district courts.” 28 U.S.C. § 1291. District
court orders that finally and conclusively “determine claims of
right separable from, and collateral to, rights asserted in the
[underlying] action” are final for purposes of § 1291 and are
immediately appealable. Cohen v. Beneficial Indus. Loan
Corp., 337 U.S. 541, 546 (1949). “[A] district court’s denial of
a claim of [official] immunity, to the extent that it turns on an
issue of law, is an appealable ‘final decision’” under the
collateral order doctrine because official immunity is an
entitlement to avoid the costs of trial and the burdens of broad-
reaching discovery. Mitchell v. Forsyth, 472 U.S. 511, 526,




                               11
530 (1985); see also Kulwicki v. Dawson, 969 F.2d 1454,
1460–61, 1461 n.7 (3d Cir. 1992) (noting that, unlike a factual
claim, such as “the ‘I didn’t do it’ defense,” which “relates
strictly to the merits of the plaintiff’s claim,” a claim of official
immunity is immediately appealable under the collateral order
doctrine). An interlocutory order appealable under the
collateral order doctrine must be appealed within thirty days of
its entry. Fed. R. App. P. 4(a)(1)(A); see also In re Montgomery
County, 215 F.3d 367, 372 (3d Cir. 2000) (“The Rule 4(a)
deadline for civil cases applies to all appealable orders,
including collateral orders, specifically orders denying
immunity.” (internal quotation marks and citation omitted)).
        Our jurisdiction over the immunity determinations in
the April 2019 order, which Vernon appealed within thirty
days of its entry, is fairly straightforward.
        First, the April 2019 order conclusively determined that
Vernon is not entitled to absolute immunity. In the September
2018 order, the District Court set out the standard, stating that
a prosecutor enjoys absolute immunity “[i]n initiating a
prosecution and in presenting the State’s case” but not for
“investigative evidence-gathering.” Weimer I, 2018 WL
4404049, at *8 (citations omitted). The Court then permitted
Weimer to amend her complaint to allege that Vernon engaged
in investigatory misconduct, which would not be protected by
prosecutorial immunity. When Weimer amended her
complaint, Vernon again moved to dismiss, arguing Weimer
was granted limited leave to amend to allege specific
investigatory wrongdoing by Vernon but failed to do so. In
rejecting her argument, the District Court conclusively denied
Vernon’s entitlement to absolute immunity at the motion-to-
dismiss stage. 5 See Weimer II, 2019 WL 1509664, at *9–10,

5
    Specifically, the District Court stated that Weimer’s Second




                                 12
12.
       Second, the April 2019 order conclusively denied
qualified immunity on the failure to intervene claim. Although
the District Court said it might revisit Vernon’s entitlement to
immunity at a later stage in the litigation, the practical effect of
the order was to require Vernon to proceed to discovery on this
claim, despite her argument that she should not be required to
do so. See Oliver v. Roquet, 858 F.3d 180, 188 (3d Cir. 2017);
George v. Rehiel, 738 F.3d 562, 571 (3d Cir. 2013).
       Our jurisdiction over the September 2018 order is more
complicated, but we need not decide whether that order,
granting leave to amend, was immediately appealable. Even if
the District Court’s conclusion regarding the bite-mark
investigation in its September 2018 order was immediately
appealable under the collateral order doctrine, Vernon’s failure
to appeal within thirty days did not deprive her of the
opportunity to appeal the order’s adverse rulings because
another appealable order—the April 2019 order—was
subsequently entered and timely appealed. Indeed, “several
courts of appeals have held explicitly, across a wide range of

Amended Complaint “makes multiple allegations of Vernon’s
involvement in the police investigation” and, therefore, Vernon
is not entitled to absolute immunity on the civil rights
conspiracy or failure to intervene claims. Weimer II, 2019 WL
1509664, at *9–10. To support this holding the District Court
cited a list of paragraphs in the Second Amended Complaint.
See Odd, 539 F.3d at 210. Here, we conclude we have
jurisdiction to review the District Court’s denial of absolute
immunity, and, below, in Part III.A, we proceed to parse the
Second Amended Complaint to determine whether Weimer
alleges investigative conduct, to which absolute immunity
would not apply.




                                13
collateral order appeal circumstances, that failure to take an
available collateral order appeal does not forfeit the right to
review the order on appeal from a final judgment,” as long as
the issue has not become moot. 15A Charles Alan Wright,
Arthur R. Miller & Edward H. Cooper, Federal Practice and
Procedure § 3911 & n.78 (2d ed. 2020) (collecting cases).
        One of our sister circuits has taken this concept a step
further, holding it had jurisdiction to review two interlocutory
orders—both of which effectively denied sovereign immunity
to Iran—even though Iran failed to appeal the earlier of the two
orders within thirty days. Rubin v. Islamic Republic of Iran,
637 F.3d 783, 790–92 (7th Cir. 2011). The court stated that
“[t]he failure to timely appeal an immunity order under the
collateral-order doctrine . . . postpones review until another
appealable order”—including an interlocutory order—“is
entered.” Id. at 791. Therefore, “Iran’s timely appeal of [the
later-in-time collateral] order permit[ted] review of the
earlier—and closely related—immunity decision.” Id. We, too,
have suggested that if the Rule 4(a) deadline is missed, the
order is not immediately appealable and the party “must then
wait until another appealable order . . . is entered, upon appeal
of which [s]he can challenge any interlocutory order that has
not become moot.” In re Montgomery County, 215 F.3d at 372
(citation omitted). Here, we have jurisdiction over the
immunity rulings in the September 2018 order because the
April 2019 order—which dealt with closely related immunity
questions at the motion-to-dismiss stage—was an appealable
order, Vernon appealed within the thirty-day window, and the
immunity issue was not moot.
        A contrary holding would contravene “the historic
federal policy against piecemeal appeals.” Sears, Roebuck &
Co. v. Mackey, 351 U.S. 427, 438 (1956); see also Fed. Home
Loan Mortg. Corp. v. Scottsdale Ins. Co., 316 F.3d 431, 438




                               14
(3d Cir. 2003) (the “finality requirement of 28 U.S.C. § 1291
is grounded ‘not in merely technical conceptions of finality,’
but rather on a long-recognized policy ‘against piecemeal
litigation’” (quoting Catlin v. United States, 324 U.S. 229,
233–34 (1945))). Under the circumstances of this case,
requiring Vernon to either file two separate appeals at the
motion-to-dismiss stage or risk forfeiting her appellate rights
would be inconsistent with this long-recognized tradition. 6

6
  Weimer argues that Vernon waived her opportunity to appeal
the denial of qualified immunity for her alleged conduct in
directing police to investigate the bite mark. In her motion to
dismiss the Second Amended Complaint, Vernon stated that
several of Weimer’s claims should be dismissed and Weimer
“should only be permitted to proceed on her malicious
prosecution claim against Vernon for [Vernon’s] alleged
involvement in securing bite[-]mark evidence.” App. 136–37.
Given the unique circumstances of this case, the procedural
posture before the District Court, and the rule we describe
above, we do not see this statement or Vernon’s failure to re-
raise the issue of qualified immunity regarding the bite-mark
investigation in her second motion to dismiss as fatal to her
appeal of that issue. Because the District Court granted
Vernon’s first motion to dismiss in large measure but gave
Weimer limited leave to amend her complaint, Vernon would
have reasonably understood that her arguments in the second
motion to dismiss should have been directed only to those
issues for which Weimer had been granted leave to amend.
Accordingly, Vernon’s acknowledgement in her motion before
the District Court that she would not relitigate issues the
District Court had already decided in the September 2018 order
did not amount to a waiver of her appellate rights over this
argument.




                              15
        Finally, although Vernon’s notice of appeal designates
only the April 2019 order as the order on appeal, we may still
consider the District Court’s bite-mark rulings in the
September 2018 order. Federal Rule of Appellate Procedure
3(c)(1)(B) requires that a notice of appeal “designate the
judgment, order, or part thereof being appealed.” However, we
“liberally construe[] notices of appeal.” Sulima v. Tobyhanna
Army Depot, 602 F.3d 177, 184 (3d Cir. 2010) (citation
omitted). We may “exercise jurisdiction over orders not
specified in the [n]otice of [a]ppeal if: (1) there is a connection
between the specified and unspecified orders; (2) the intention
to appeal the unspecified order is apparent; and (3) the
opposing party is not prejudiced and has a full opportunity to
brief the issues.” Id. (internal quotation marks and citation
omitted). Here, there is a connection between the September
2018 order addressing Vernon’s first motion to dismiss on
immunity grounds and the April 2019 order, in which the
District Court conclusively determined that, for the balance of
Weimer’s claims, Vernon was not entitled to dismissal based
on immunity. Vernon’s intent to appeal the District Court’s
denial of qualified immunity regarding her investigation into
the bite mark is clear from her opening brief. And Weimer was
not prejudiced because she had the opportunity to respond, and
did respond, to Vernon’s argument on the merits in her
answering brief.
                               III
        Having assured ourselves of our jurisdiction, we turn to
the merits. Vernon argues that the District Court erred in failing
to dismiss certain of Weimer’s claims against her because she
is entitled to (A) absolute immunity on all of Weimer’s § 1983
claims and (B) qualified immunity on the failure to intervene
claim and for her alleged involvement in directing officers to
investigate the timing of the bite-mark evidence. Our review of




                                16
these issues is plenary. Yarris v. County of Delaware, 465 F.3d
129, 134 (3d Cir. 2006).
A. Absolute Immunity
        Section 1983 “provides that every person who acts
under color of state law to deprive another of a constitutional
right shall be answerable to that person in a suit for damages.”
Imbler v. Pachtman, 424 U.S. 409, 417 (1976) (internal
quotation marks and alteration omitted). However, the
Supreme Court “has consistently recognized” that the statute
“was not meant to abolish wholesale all common-law
immunities” available at the time of its enactment in 1871.
Burns v. Reed, 500 U.S. 478, 484 (1991) (internal quotation
marks and citation omitted). Thus, some officials are entitled
to “absolute protection from damages liability” because they
“perform special functions” similar “to functions that would
have been immune when Congress enacted § 1983.” Fogle,
957 F.3d at 158 (internal quotation marks and citation omitted).
        Noting both “a common law tradition of prosecutorial
immunity and strong policy considerations that supported
extending immunity to the § 1983 context,” the Supreme Court
has held that prosecutors are immune from suit when they
perform prosecutorial functions. Odd, 538 F.3d at 208 (citing
Imbler, 424 U.S. at 420–21, 424). The defense does not protect
a prosecutor’s actions wholesale merely because she is a
prosecutor. Fogle, 957 F.3d at 159. Rather, absolute immunity
“attaches [only] to actions intimately associated with the
judicial phases of litigation, . . . not to administrative or
investigatory actions unrelated to initiating and conducting
judicial proceedings.” Odd, 538 F.3d at 208 (internal quotation
marks and citation omitted). The prosecutor “seeking absolute
immunity bears the burden of showing that such immunity is
justified for the [specific] function in question.” Fogle, 957




                              17
F.3d at 159 (quoting Burns, 500 U.S. at 486). “[T]o earn the
protections of absolute immunity” at the motion-to-dismiss
stage, “a defendant must show that the conduct triggering
absolute immunity ‘clearly appear[s] on the face of the
complaint.’” Id. at 161 (second alteration in original) (quoting
Wilson v. Rackmill, 878 F.2d 772, 776 (3d Cir. 1989)).
        Determining which of a prosecutor’s actions were
prosecutorial in nature “is a fact-specific” inquiry. Id. at 160.
We must “ascertain just what conduct forms the basis for the
plaintiff’s cause of action” and “[t]hen . . . determine what
function (prosecutorial, administrative, investigative, or
something else entirely) that act served.” Id. at 161 (internal
quotation marks and citation omitted). Importantly, “while we
tend to discuss prosecutorial immunity based on alleged acts,
our ultimate analysis is whether a defendant has established
absolute prosecutorial immunity from a given claim.” Id.
       As relevant to this appeal, Weimer asserts three claims
against Vernon: malicious prosecution, civil rights conspiracy,
and failure to intervene. The September 2018 order held that
all the allegations in support of these claims (aside from
Vernon’s participation in the bite-mark investigation) involved
prosecutorial misconduct. However, in the April 2019 order,
the District Court broadly concluded that Weimer’s Second
Amended Complaint “makes multiple allegations of Vernon’s
involvement in the police investigation,” so Vernon’s
entitlement to absolute immunity was not clear on the face of
the complaint. 7 Weimer II, 2019 WL 1509664, at *9.


7
  The April 2019 order addressed only whether the Second
Amended Complaint pleaded investigative acts to support the
civil rights conspiracy and failure to intervene claims. It did not
address the malicious prosecution claim. To be sure, the




                                18
       To support this holding, the District Court cited
numerous paragraphs in the Second Amended Complaint.
However, it failed to “dissect[]” Vernon’s alleged actions to
determine whether they were prosecutorial or investigative in
nature. Odd, 538 F.3d at 210. Thus, we must now “defin[e]
[each] act” that Weimer added to her Second Amended
Complaint to determine whether the District Court erred in



September 2018 order had already held that the malicious
prosecution claim remained viable to the extent it was
premised upon Vernon’s investigation into the bite mark. But
that order also, as for the other claims, granted Weimer “leave
to file a second amended complaint to identify specific
wrongful investigatory acts by Vernon” to further support the
malicious prosecution claim. Weimer I, 2018 WL 4404049, at
*10. Vernon’s motion to dismiss the Second Amended
Complaint reasserted absolute immunity as to all claims for
which Weimer was granted leave to amend, including the
malicious prosecution claim. It seems to us an oversight that
the District Court failed to address whether the newly pleaded
allegations in the Second Amended Complaint could also serve
as factual bases for the malicious prosecution claim.
Accordingly, even though, as we explain in Part III.B.2,
Vernon is entitled to qualified immunity on the malicious
prosecution claim to the extent the claim is premised on her
investigation into the bite-mark evidence, we think the
malicious prosecution claim may remain viable to the extent it
is premised on other investigative activities—including, as we
describe above, Vernon’s involvement at the crime scene and
investigation into witness statements—to which absolute
immunity does not apply and for which qualified immunity
was not requested.




                              19
concluding that these actions were investigative. 8 See Fogle,
957 F.3d at 161 (alterations in original) (quoting Odd, 538 F.3d
at 212).
       1. Involvement at the Crime Scene
        According to the Second Amended Complaint, Vernon
arrived at Haith’s apartment a few hours after the Connellsville
Police Department because a Connellsville detective
“requested [her presence at] the crime scene so that she could
be involved in and help to direct the murder investigation from
the onset of the investigation.” App. 86 ¶ 23. During their
initial search of the crime scene, officers recovered DNA
samples, found drug-related evidence, and learned that Haith
had attended parties the night before and morning of his
murder. The initial crime-scene investigation led police to
interview Weimer because she had attended one of these
parties. And, although “DNA testing performed at the crime
scene” and later “on . . . Weimer’s clothing” confirmed
Weimer’s account of her whereabouts from the night before
and suggested “an unidentified male” was involved in Haith’s
murder, App. 88 ¶ 32, investigators zeroed in on Weimer,
ignoring evidence from the crime scene and other potential
leads.
        Vernon’s alleged role in the initial crime-scene
investigation was investigative in nature. Although we must be

8
  Vernon appears to concede that she was functioning as an
investigator when she investigated the bite-mark evidence. In
her opening brief, she argues that she is entitled only to
qualified immunity, not absolute immunity, for her alleged
participation in the bite-mark investigation. Therefore, we will
not separately parse out this conduct to assess whether it was
prosecutorial or investigative in nature.




                              20
wary of “bright-line rules that would treat the timing of the
prosecutor’s action” as dispositive, Vernon’s alleged act of
helping to direct the crime-scene investigation occurred long
before a criminal complaint had been drafted and before any
suspect had even been identified. See Odd, 538 F.3d at 210.
Thus, these allegations “point[] more convincingly to
‘investigation’ than to ‘prosecution.’” See Kulwicki, 969 F.2d
at 1466.
        2. Participation in Interviews of and Reliance on
           Statements by Beal, Blair, and Stenger
        The Second Amended Complaint alleges that Vernon
and the police investigators manipulated evidence and
knowingly continued to investigate contradictory witness
statements in the period leading up to Weimer’s arrest.
Specifically, Vernon and the police continued to rely on Beal’s
statements, despite the fact that one of his versions of Haith’s
murder involved a man named “Lonnie,” who was incarcerated
at the time of the murder. In addition, Vernon and several
officers interviewed Blair at Vernon’s office, and, based on
that interview and the contradictory statement allegedly written
by Stenger, Vernon helped assemble a dive team to search a
pond for evidence and interviewed Stenger’s counsel. Even
though the written statement contradicted Blair’s account of
Stenger’s involvement, and even though Stenger’s counsel
denied that Stenger had authored the statement, the
investigators continued to rely on the written statement in their
investigation into Weimer.
       Given these allegations (which we assume here to be
true), Vernon cannot show that the defense of absolute
immunity appears clearly on the face of the complaint. See
Fogle, 957 F.3d at 161. This alleged conduct—investigating
leads before criminal charges have been filed—is more akin to




                               21
“the detective’s role in searching for the clues and
corroboration that might give h[er] probable cause to
recommend that a suspect be arrested” than “the advocate’s
role in evaluating evidence and interviewing witnesses as [s]he
prepares for trial.” Buckley v. Fitzsimmons, 509 U.S. 259, 273
(1993); see id. at 274–75 (holding prosecutors were acting as
detectives rather than advocates when they investigated a
bootprint because, at the time, they lacked probable cause to
arrest or initiate judicial proceedings against the suspect). And,
again, although we resist bright-line rules based on the timing
of the prosecutor’s alleged activities, the Second Amended
Complaint alleges that this misconduct occurred months before
Weimer was charged with Haith’s murder.
       3. Approval of the Criminal Complaint
       Weimer’s Second Amended Complaint alleges that
“nearly three years after . . . Haith’s murder,” the investigation
had “uncovered statements made by three different persons—
Beal, Blair and Stenger—that were patently inconsistent, and .
. . contradicted by known DNA evidence.” App. 93 ¶ 53.
Nevertheless, Vernon and several officers “agreed to proceed
with filing criminal charges against” Weimer. App. 93 ¶ 54.
The officers then prepared a criminal complaint, which Vernon
approved.
        Vernon’s approval of the criminal complaint is
protected by prosecutorial immunity. We have long maintained
that “[t]he decision to initiate a prosecution is at the core of a
prosecutor’s judicial role.” Kulwicki, 969 F.2d at 1463; see
also Kalina v. Fletcher, 522 U.S. 118, 129 (1997) (holding a
prosecutor’s “activities in connection with the preparation and
filing” of a criminal information and motion for arrest were
protected by absolute immunity).
                            *        *     *




                                22
        In sum, Vernon is entitled to absolute immunity only for
her alleged conduct in deciding to file and approving the
criminal complaint against Weimer. She is entitled to absolute
immunity neither for her alleged involvement at the crime
scene on the morning of Haith’s murder, nor for her
investigation into statements by Beal, Blair, and Stenger. To
the extent that this investigatory conduct forms the basis of
Weimer’s malicious prosecution, civil rights conspiracy, and
failure to intervene claims against Vernon, we will affirm the
District Court’s denial of Vernon’s motion to dismiss these
claims based on absolute immunity. 9

9
  Weimer also alleges that after her convictions were vacated,
“the individual Defendants continued to act in concert to cover
up and suppress the wrongful actions that led to [her] wrongful
convictions,” and they “attempted to create additional evidence
. . . with the intent of re-prosecuting [her] for . . . Haith’s
murder.” App. 100–01 ¶ 86. Vernon argues that any allegations
in the Second Amended Complaint “regarding an after-the-fact
cover-up are not investigatory.” Appellants’ Br. 24. From our
review of the Second Amended Complaint, it appears that
Weimer alleges broadly that all the defendants worked together
to cover up their involvement in the wrongful investigation, but
Weimer does not set out any specific wrongful conduct by
Vernon during this period. Based on the lack of specificity in
the Second Amended Complaint, and based on the fact that
Vernon was, by this point, a sitting Court of Common Pleas
Judge in Fayette County, it is exceedingly difficult for us to
determine whether Vernon would be entitled to absolute
immunity for any alleged conduct after Weimer’s convictions
were vacated and during her pretrial proceedings in 2016.
Therefore, we note only that, insofar as Weimer’s claims
against Vernon remain premised on Vernon’s alleged




                              23
B. Qualified Immunity
        “Prosecutors who are not entitled to absolute immunity
from a plaintiff’s claims may nonetheless be entitled to
qualified immunity from those same claims.” Yarris, 465 F.3d
at 139. Under the now-familiar standard for the judge-created
defense of qualified immunity, a state officer is shielded from
a suit for monetary damages under § 1983 unless “the official
violated a . . . constitutional right,” and “the right was clearly
established at the time of the challenged conduct.” Ashcroft v.
al-Kidd, 563 U.S. 731, 735 (2011) (internal quotation marks
and citation omitted). “[A] defendant cannot be said to have
violated a clearly established right unless the right’s contours
were sufficiently definite that any reasonable official in the
defendant’s shoes would have understood that [s]he was
violating it.” Plumhoff v. Rickard, 572 U.S. 765, 778–79
(2014). That is, the legal rule must have been “dictated by
controlling authority or a robust consensus of cases of
persuasive authority.” District of Columbia v. Wesby, 138 S.
Ct. 577, 589–90 (2018) (internal quotation marks and citation
omitted). The Supreme Court has repeatedly emphasized that
“clearly established law should not be defined at a high level
of generality.” White v. Pauly, 137 S. Ct. 548, 552 (2017) (per
curiam) (internal quotation marks omitted). “A rule is too
general if the unlawfulness of the [official’s] conduct does not
follow immediately from the conclusion that the rule was
firmly established.” Wesby, 138 S. Ct. at 590 (alteration,
internal quotation marks, and citation omitted).
       Vernon contends she is entitled to qualified immunity

participation in an after-the-fact cover up or an effort to
prosecute Weimer anew, any absolute immunity defense is not
apparent on the face of the Second Amended Complaint. See
Fogle, 957 F.3d at 161.




                               24
for her failure to intervene in the allegedly unconstitutional
police investigation and for directing police to investigate the
timing of the bite mark on Haith’s hand.
       1. Failure to Intervene in the Police Investigation
       Weimer alleges that Vernon participated in the reckless
and deliberately indifferent police investigation and “had
reasonable and realistic opportunities to intervene to prevent
the violations of . . . Weimer’s constitutional rights.” App. 109
¶ 123. Vernon responds that she is entitled to qualified
immunity because, “at the time of the allegations, no clearly
established [law] existed to put [her] on notice” that, as a
prosecutor, her failure to intervene in the police investigation
would violate Weimer’s rights. Appellants’ Br. 30. We agree.
       It is well established in our Circuit that both police and
corrections officers must “take reasonable steps to protect a
victim from another officer’s use of excessive force.” Smith v.
Mensinger, 293 F.3d 641, 650 (3d Cir. 2002); see also Baker
v. Monroe Twp., 50 F.3d 1186, 1193–94 (3d Cir. 1995). But
we have not extended this duty to prosecutors who fail to
intervene to prevent police from conducting unconstitutional
investigations. Accordingly, we cannot say that “any
reasonable [prosecutor]” investigating Haith’s murder would
have understood that she was violating Weimer’s
constitutional rights in failing to intervene to prevent improper
investigatory conduct by police. See Plumhoff, 572 U.S. at
778–79. Put differently, the facts here are simply too dissimilar
from those in the excessive force cases for us to hold that those
cases would have put Vernon on notice that her actions were
unlawful.
       Although the District Court acknowledged that there
was no “case law in the Third Circuit holding a prosecutor
liable for a failure to intervene in the conduct of police




                               25
officers,” it identified “[a] subsequent decision from the
[Western District of Pennsylvania that] ha[d] extended liability
for a failure to intervene claim to prosecutors who [were]
engaging in investigative conduct.” Weimer II, 2019 WL
1509664, at *10 (citing Fogle v. Sokol, No. 17-194, 2018 WL
6831137 (W.D. Pa. Dec. 28, 2018), aff’d 957 F.3d at 148).10
Thus, the District Court permitted Weimer’s claim to proceed
“[g]iven the recent developments in this area of the law and the
early stage of this case.” Id. at *12. However, a district court
opinion from 2018 cannot serve as a basis for holding that a
prosecutor’s duty to intervene to prevent an unconstitutional
police investigation was clearly established between 2001 and
2006. For a legal principle to be clearly established, it must be
based on precedent existing at the time of the official’s act, and
the holding of one district judge, which “is not controlling
authority in any jurisdiction, much less in the entire United
States,” is insufficient to clearly establish a violation of a
constitutional right. al-Kidd, 563 U.S. at 741–42 (internal
quotation marks omitted); see also Fogle, 2018 WL 6831137,
at *11–12 (defining its holding as an “extension” of our
excessive force case law to prosecutors).11

10
   Our opinion on appeal in Fogle merely affirmed the trial
court’s denial of the prosecutors’ motion to dismiss Fogle’s
claims based on absolute immunity. Fogle, 957 F.3d at 165.
Here, in contrast, Vernon has not only requested absolute
immunity on the failure to intervene claim, but she also claims
that if absolute immunity does not shield her from suit on this
claim, qualified immunity applies.
11
   District courts appear to disagree as to whether prosecutors
have a duty to intervene in police investigations. See Patrick v.
City of Chicago, 213 F. Supp. 3d 1033, 1054–55 (N.D. Ill.
2016) (noting courts within its district “are split on whether




                               26
       Finally, Weimer argues that “the proper inquiry is
whether, at the time of the events in 2001 [to] 2004, [she] had
the [c]onstitutional right to be free from a reckless and
deliberately indifferent police investigation.” Appellee’s Br.
24. Yet this obscures the fact that Weimer specifically asserted
a failure to intervene claim. Whatever might be said of the
investigation, the question here is whether Weimer had a
clearly established right to have Vernon take reasonable steps
to protect her from an unconstitutional police investigation.
The Supreme Court has “repeatedly told courts . . . not to define
clearly established law at a high level of generality.” al-Kidd,
563 U.S. at 742. Weimer’s reframing of the constitutional
violation at issue does not change the fact that there was no
clearly established law at the time of Vernon’s allegedly
violative conduct that would have placed the constitutional
question she confronted—to intervene in the police
investigation or not to intervene—“beyond debate.” See
Plumhoff, 572 U.S. at 779 (citation omitted).
       2. Investigation into the Timing of the Bite Mark
       Weimer alleges that at some point during the
investigation, Vernon told officers to investigate the timing of
the bite mark on Haith’s hand. The bite-mark expert was then

prosecutors have a duty to intervene” and recognizing that
there “are good reasons to be cautious in expanding the law . .
. to include . . . State’s Attorneys”). Disagreement among
district judges may, in and of itself, be a reason to recognize a
qualified immunity defense. See Safford Unified Sch. Dist. #1
v. Redding, 557 U.S. 364, 378 (2009) (noting lower courts had
“reached divergent conclusions regarding how the . . . standard
[at issue] applie[d],” and stating that “these differences of
opinion from our own are substantial enough to require
immunity”).




                               27
“asked to update his opinions to address and eliminate any
timing concerns.” App. 91 ¶ 45. The expert, without reviewing
additional evidence, concluded that the bite occurred shortly
before Haith’s death. The “Defendants were aware that [the
expert] was not provided any additional evidence or materials
upon which to base his additional opinions, but nevertheless”
continued “to rely upon the manufactured evidence.” App. 91
¶ 45. Vernon argues she is entitled to qualified immunity for
directing further investigation into the bite-mark evidence. We
agree.
       During the relevant time period—from late 2002 to
early 2006—the unreliability of bite-mark evidence was not
widely recognized such that “any reasonable official in
[Vernon’s] shoes would have understood that [s]he was
violating” Weimer’s rights by directing officers to investigate
the timing of the bite mark on Haith’s hand. See Plumhoff, 572
U.S. at 778–79. Despite allegations that the bite-mark expert
later referred to such evidence as “junk science” during
Weimer’s postconviction proceedings, see App. 102 ¶ 94, such
evidence was widely used in criminal proceedings during and
after Weimer’s trial, see Erica Beecher-Monas, Reality Bites:
The Illusion of Science in Bite-Mark Evidence, 30 Cardozo L.
Rev. 1369, 1375–87, 1408 (2009) (outlining the scientific
unreliability of bite-mark evidence and arguing that judges
“circumvent[] their gate-keeping responsibilities” by
“continu[ing] to admit bite-mark testimony into evidence”);
see also Brewer v. Hayne, 860 F.3d 819, 824–25 (5th Cir.
2017) (holding forensic odontologists were entitled to qualified
immunity when the plaintiffs showed only that the evidence
the experts presented at trial in the 1990s was no longer
considered trustworthy by later standards and that the experts
may have been negligent in their analysis). Thus, based on the
law as it existed at the time, Vernon was not on notice that her




                              28
alleged conduct of directing further investigation into the bite-
mark evidence would violate Weimer’s rights.
                        *       *      *
       In sum, Vernon is entitled to qualified immunity from
Weimer’s failure to intervene claim and from the malicious
prosecution claim insofar as it relies upon Vernon’s direction
to investigate the timing of the bite mark.
                               IV
        For the foregoing reasons, we will affirm in part, reverse
in part, and remand for further proceedings consistent with this
opinion. To the extent that Vernon’s alleged investigatory
conduct, as identified above, forms the basis of Weimer’s
malicious prosecution and civil rights conspiracy claims
against Vernon, we will affirm the District Court’s denial of
Vernon’s motion to dismiss these claims based on absolute
immunity. We will, however, reverse the District Court’s
denial of absolute immunity for Vernon’s approval of the
criminal complaint and its denial of Vernon’s motion to
dismiss the failure to intervene claim on the basis of qualified
immunity. We will also reverse the District Court’s denial of
qualified immunity for Vernon’s alleged conduct in directing
officers to investigate the timing of the bite mark. Because
qualified immunity shields Vernon from suit for her
investigation into the bite-mark evidence, this conduct cannot
be used to support Weimer’s malicious prosecution claim
against Vernon.




                               29
