                 FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

LORI BELTRAN; ROBERT BELTRAN;         
COBY BELTRAN, by and through his
Guardian Ad Litem Lori Beltran,
             Plaintiffs-Appellants,
               v.
SANTA CLARA COUNTY; MELISSA                 No. 05-16976
SUAREZ, individually and as an
employee of the County of Santa              D.C. No.
                                          CV-03-03767-RMW
Clara; JENNIFER HUBBS,
                                              OPINION
individually and as an employee
of the County of Santa Clara;
EMILY TJHIN, individually and as
an employee of the County of
Santa Clara,
              Defendants-Appellees.
                                      
       Appeal from the United States District Court
         for the Northern District of California
       Ronald M. Whyte, District Judge, Presiding

                 Argued and Submitted
         December 12, 2007—Pasadena, California

                  Filed January 24, 2008

  Before: Alex Kozinski, Chief Judge, Stephen Reinhardt,
       Andrew J. Kleinfeld, Michael Daly Hawkins,
       Kim McLane Wardlaw, William A. Fletcher,
  Ronald M. Gould, Richard A. Paez, Marsha S. Berzon,
  Richard R. Clifton and Sandra S. Ikuta, Circuit Judges.

                    Per Curiam Opinion

                           1201
                   BELTRAN v. SANTA CLARA                1203


                         COUNSEL

Robert R. Powell and Dennis R. Ingols, The Law Offices of
Robert R. Powell, San Jose, California, for the plaintiffs-
appellants.

Melissa R. Kiniyalocts, Deputy County Counsel, and Ann
Miller-Ravel, County Counsel, Santa Clara County, San Jose,
California, for the defendants-appellees.


                         OPINION

PER CURIAM:

   1. Melissa Suarez, a social worker for Santa Clara County’s
child protective services, investigated whether Lori Beltran
was abusing her son, Coby. After this investigation, Suarez’s
supervisor Emily Tjhin filed a child dependency petition,
which Tjhin signed under penalty of perjury. This petition
included a three-page statement of facts describing the find-
ings of Suarez’s investigation. Suarez also filed a separate
custody petition, which she signed under penalty of perjury.
The custody petition attached and incorporated by reference
the three-page statement of facts from the dependency peti-
tion.
1204                BELTRAN v. SANTA CLARA
   The dependency petition was denied, Coby was returned to
his parents, and the Beltrans sued Suarez and Tjhin under 42
U.S.C. § 1983, charging constitutional violations in removing
Coby from the Beltrans’ custody and attempting to place him
under the supervision of the state. Specifically, the Beltrans
claimed that Suarez and Tjhin fabricated much of the infor-
mation in the three-page statement of facts. Relying on Doe
v. Lebbos, 348 F.3d 820, 825-26 (9th Cir. 2003), the district
court held that Suarez and Tjhin had absolute immunity for
their actions connected to signing and filing the dependency
and custody petitions—including the alleged fabrication of
evidence and false statements. It therefore dismissed plain-
tiffs’ claims that were based on the allegedly false petition
statements. The district court eventually granted summary
judgment to the defendants on the remainder of plaintiffs’
claims, but those issues are not before us, as plaintiffs appeal
only the dismissal of claims based on absolute immunity.

   [1] 2. Parties to section 1983 suits are generally entitled
only to immunities that existed at common law. Imbler v.
Pachtman, 424 U.S. 409, 417-18 (1976). We have therefore
“granted state actors absolute immunity only for those func-
tions that were critical to the judicial process itself,” such as
“ ‘initiating a prosecution.’ ” Miller v. Gammie, 335 F.3d 889,
896 (9th Cir. 2003) (en banc) (quoting Imbler, 424 U.S. at
431). It follows that social workers have absolute immunity
when they make “discretionary, quasi-prosecutorial decisions
to institute court dependency proceedings to take custody
away from parents.” Id. at 898. But they are not entitled to
absolute immunity from claims that they fabricated evidence
during an investigation or made false statements in a depen-
dency petition affidavit that they signed under penalty of per-
jury, because such actions aren’t similar to discretionary
decisions about whether to prosecute. A prosecutor doesn’t
have absolute immunity if he fabricates evidence during a
preliminary investigation, before he could properly claim to
be acting as an advocate, see Buckley v. Fitzsimmons, 509
U.S. 259, 275 (1993), or makes false statements in a sworn
                    BELTRAN v. SANTA CLARA                  1205
affidavit in support of an application for an arrest warrant, see
Kalina v. Fletcher, 522 U.S. 118, 129-30 (1997). Further-
more, as prosecutors and others investigating criminal matters
have no absolute immunity for their investigatory conduct, a
fortiori, social workers conducting investigations have no
such immunity. See id. at 126.

   [2] The district court’s error is perfectly understandable, as
it relied on our incorrect ruling in Doe v. Lebbos, which we
overrule today. We reverse the district court’s ruling that
defendants are entitled to absolute immunity and remand for
further proceedings consistent with this opinion.

  REVERSED AND REMANDED.
