                 FOR PUBLICATION
 UNITED STATES COURT OF APPEALS
      FOR THE NINTH CIRCUIT

OLOTH INSYXIENGMAY,                      No. 02-36017
             Petitioner-Appellant,
               v.                          D.C. No.
                                         CV-00-05500-RJB
RICHARD MORGAN,
                                            OPINION
             Respondent-Appellee.
                                     
       Appeal from the United States District Court
         for the Western District of Washington
        Robert J. Bryan, District Judge, Presiding

                 Argued and Submitted
          October 4, 2004—Seattle, Washington

                  Filed March 30, 2005

    Before: Dorothy W. Nelson, Stephen Reinhardt, and
            Sidney R. Thomas, Circuit Judges.

               Opinion by Judge Reinhardt




                           3803
                    INSYXIENGMAY v. MORGAN                  3807
                          COUNSEL

Nancy D. Tenney and Laura E. Mate, Federal Public Defend-
er’s Office, Seattle, Washington, for the petitioner-appellant.

Christine O. Gregoire and John J. Samson, Office of the
Washington Attorney General, Olympia, Washington, for the
respondent-appellee.


                          OPINION

REINHARDT, Circuit Judge:

   Oloth Insyxiengmay was convicted of two counts of mur-
der in the first degree and two counts of assault in the first
degree for an attack on four high school teens who egged his
gang’s hangout. Following his conviction and a series of
appeals in the Washington state courts, Insyxiengmay peti-
tioned the district court for a writ of habeas corpus. He now
contends that the district court erred in dismissing three of the
six claims on the ground that the claims were procedurally
barred and denying his Sixth Amendment claim that he and
his counsel were improperly excluded from an in camera
hearing regarding a confidential informant. The three claims
that the district court dismissed on procedural grounds are that
the trial court failed to give a manslaughter instruction (claim
1), that a non-testifying co-defendant’s statement inculpating
Insyxiengmay should not have been received in evidence
(claim 2), and that the prosecution’s key witness’s adverse
polygraph examination results should have been admitted
(claim 6). Because Insyxiengmay timely presented the claims
to the Washington Supreme Court as federal issues, and
because his allegations regarding his Sixth Amendment claim
necessitated an evidentiary hearing in federal court, we
reverse the district court’s dismissal of his petition and
remand for consideration of his claims.
3808                   INSYXIENGMAY v. MORGAN
I.       FACTUAL AND PROCEDURAL BACKGROUND

A.       The Crime

   On August 24, 1994, four high school boys drove down a
Tacoma, Washington street throwing eggs at houses. Some of
those eggs splattered on “the snake house,” a hangout for a
local gang called the Original Loco Boyz. Oloth Insyxieng-
may, Nga Ngoeung, and Soutthanom Misaengsay1 were asso-
ciated with the gang. All three were juveniles in 1994;
Insyxiengmay was fifteen years old.

   Insyxiengmay, Ngoeung, and Misaengsay were outside the
snake house during the egging. Believing that the attack was
gang-related, Insyxiengmay entered the house and grabbed
the owner’s rifle. All three boys scrambled into a silver Buick
and, with Ngoeung driving, proceeded to follow the other car.
According to Misaengsay, it was Insyxiengmay who put the
rifle out of the window and fired at the other boys’ car. The
driver and front seat passenger of that car were shot and
killed.

   The three returned to the snake house after the shootings.
Insyxiengmay handed the rifle to Wendy West, the only per-
son present in the house, and told her to get rid of it. Insy-
xiengmay said, “We shot them up. We shot them up. They
threw eggs at us, the Rickets. We shot them up.” West testi-
fied that Insyxiengmay was highly upset: “He’s usually smil-
ing and happy, and he was almost — he was real fearful. He
was almost in a state of tears.” Meanwhile, she said, Misaeng-
say was “smirking and almost laughing.”

  Insyxiengmay was arrested on September 1, 1994. After
being advised of his rights, he agreed to make a statement. He
     1
   The trial transcript refers to the defendants by their gang names which,
respectively, are Tiny Snoopy, Shamrock, and Candyman. However, we
will refer to them by their legal surnames.
                      INSYXIENGMAY v. MORGAN                       3809
admitted to being in the car during the shootings, but he
denied being the shooter. He accused a fourth person, known
as J-Rock, instead.2

  Ngoeung was arrested two days later on September 3,
1994, based upon information as to his whereabouts provided
by a confidential informant. Ngoeung confessed to police that
he drove the car during the shootings.

   Misaengsay was also arrested on September 3rd. He ini-
tially told the police that a fourth person present in the car was
the one who was responsible for the shootings. However,
when the police falsely told him that Insyxiengmay had impli-
cated him as the shooter, he changed his statement to indicate
that no fourth person was present and instead accused Insy-
xiengmay of being the shooter. Misaengsay subsequently
entered into a plea agreement in which he agreed to testify
and to plead guilty in exchange for the state’s promise not to
charge him as an adult. Subsequently, Misaengsay pled as a
juvenile. Although Insyxiengmay was fifteen at the time and
had no prior convictions, he was eventually tried along with
Ngoeung as an adult.

B.    Confidential Informant

   During pretrial motion hearings, the prosecutor revealed to
defense counsel that a confidential informant had provided
information leading to Ngoeung’s arrest and that the infor-
mant was a passenger in one of the two cars stopped on Sep-
tember 3rd when Ngoeung was arrested. The prosecutor
further informed counsel that the arresting deputy’s report
regarding the arrest of Ngoeung falsely stated that he was on
  2
    The Washington Court of Appeals stated that Insyxiengmay named a
person known as “Sin Dog” as the fourth person. It does appear that Insy-
xiengmay named “Sin Dog” at some point during the investigation, but the
statement Insyxiengmay gave to the police (the statement made available
to the jury at trial) names “J-Rock” as the fourth person.
3810                INSYXIENGMAY v. MORGAN
routine surveillance when he located Ngoeung’s car. In truth,
the deputy “got a phone call from one of the individuals that
was in the car with these people traveling down the freeway.”
Because the prosecutor was not willing to reveal the identity
of the informant, defense counsel moved for disclosure. The
state judge subsequently held an in camera hearing to discuss
the potential testimony of the confidential informant. The
only witness who appeared at the in camera hearing was the
deputy sheriff who arrested the defendants. The judge barred
defense counsel from the hearing, refused to take his written
questions so that they could be read to the witness by the
court, did not compel the confidential informant to appear at
the hearing, and issued a protective order prohibiting defense
counsel from discussing the existence of the confidential
informant with Insyxiengmay and his co-defendant.

   Deputy Cassio, the only witness at the in camera hearing,
was the arresting officer who had falsified his report of the
arrest. He testified at the hearing that he received a phone call
from Kong Prak, an informant, on the day of the arrest alert-
ing him to Ngoeung’s location. Cassio informed the court
that, like the defendants, Prak was a member of the Original
Loco Boyz and had regularly provided reliable information
regarding the “activities of different members of th[e] gang.”
The trial court did not question Cassio about what information
Prak had provided regarding the shootings or whether, to his
knowledge, Prak had information that could be helpful to the
defense. The court asked only whether, “to [Cassio’s] knowl-
edge, [Prak was] present at the snake house during the time
surrounding the events when this murder occurred?” Follow-
ing the in camera hearing, the court announced that it had
determined that the confidential informant could not provide
any information that would be of assistance or benefit to the
defendants.

C.     The Trial

   The case against Insyxiengmay proceeded to trial. Insy-
xiengmay contends that during the trial, the judge erroneously
                    INSYXIENGMAY v. MORGAN                   3811
admitted a statement by one of Insyxiengmay’s co-defendants
which implicated Insyxiengmay, refused to admit the adverse
polygraph examination results of the state’s key witness, Mis-
aengsay, and failed to give a manslaughter instruction. Insy-
xiengmay did not testify in his own defense, having waived
his right to do so, although he sought unsuccessfully to
rescind the waiver at a later point in the trial.

   The jury rejected the charges of premeditated murder
against Insyxiengmay, but found him guilty of two counts of
murder in the first degree, based upon the element of extreme
indifference to human life, and two counts of first degree
assault. Ngoeung was convicted of two counts of aggravated
first degree murder and two counts of first degree assault.3
Insyxiengmay was sentenced to over 72 years in prison.

  On August 18, 1998, Insyxiengmay timely appealed his
conviction and sentence to the Washington Court of Appeals.
The court of appeals affirmed the conviction and the Wash-
ington Supreme Court summarily denied further review on
June 1, 1999. The mandate issued on June 17, 1999.

D.    State Habeas Proceedings

   On May 31, 2000, Insyxiengmay, acting pro se, initiated
his first personal restraint petition (“PRP”) in the Washington
Court of Appeals. In that petition, he argued that (i) the trial
judge improperly ordered him to serve his sentences consecu-
tively; (ii) the trial judge gave the wrong burden of proof
instruction; (iii) he had been denied his right to a speedy trial
as a result of the joinder of his trial with his co-defendant’s;
(iv) he had been denied his constitutional right to a unanimous
verdict; and (v) he had been denied his constitutional due pro-
cess right to full discovery.
  3
  Ngoeung was also convicted of taking a motor vehicle without the
owner’s permission.
3812                INSYXIENGMAY v. MORGAN
   Approximately two weeks after filing his first PRP (and
while it was still pending), Insyxiengmay filed a second PRP
with the Washington Court of Appeals. In that petition, he
raised four additional claims: (i) his Sixth Amendment right
was violated when polygraph evidence of one of the state’s
witnesses was excluded by the trial judge; (ii) the Confronta-
tion Clause was violated when a non-testifying co-defendant’s
statement implicating Insyxiengmay was received in evi-
dence; (iii) the trial judge improperly denied his motion to
sever his trial from his co-defendant’s; and (iv) the trial judge
failed to give a manslaughter instruction. Insyxiengmay
signed the second petition on Sunday, June 18, 2000, and
gave it to a prison official for filing with the court. However,
it was not received by the clerk’s office until Tuesday, June
20, 2000. As the mandate had issued on June 17, 1999, Insy-
xiengmay had until Monday, June 19, 2000, to file any PRPs.
His petition was deemed “filed” one day late.

   The court of appeals dismissed Insyxiengmay’s second
PRP on July 27, 2000. Explaining its decision, the court
stated:

    A personal restraint petition cannot be used to reliti-
    gate issues already decided on appeal. In re Lord,
    123 Wn.2d 296, 329 (1994). Nor can this court con-
    sider a petition filed more than one year after the fil-
    ing of the mandate disposing of the petitioner’s
    appeal. RCW 10.73.090(1), (3)(b). Insyxiengmay
    filed this petition after that one-year period expired.

While the court noted in the opinion that Insyxiengmay’s first
petition was under consideration, it did not discuss whether it
should have construed Insyxiengmay’s second PRP as an
amendment to the timely-filed first PRP.

   Insyxiengmay appealed the dismissal of his second PRP to
the Washington Supreme Court through a motion for discre-
tionary review. He attached a copy of his second PRP to that
                    INSYXIENGMAY v. MORGAN                     3813
motion. On November 11, 2000, the Washington Supreme
Court denied the motion on the ground that his second PRP
was not filed within one year after his conviction became
final.

  A few days later, the court of appeals dismissed the first
PRP on November 20, 2000 because “Insyxiengmay had not
demonstrated any error that entitles him to relief.” The court
did not discuss any of the issues raised in the second PRP, nor
did it discuss its dismissal of that PRP.

  Insyxiengmay timely moved the Washington Supreme
Court for discretionary review of the dismissal of his first
PRP, but that motion was denied on April 11, 2001, on the
ground that Insyxiengmay had not shown that the court of
appeals erred in dismissing his first PRP.

E.   Federal Habeas Proceedings

   On August 31, 2000, after the second PRP was dismissed
but prior to any state court decision on the claims submitted
in the first PRP, Insyxiengmay, acting pro se, petitioned the
district court for a writ of habeas corpus, pursuant to 28
U.S.C. § 2254. Insyxiengmay raised six issues in that petition.
The district court dismissed it without prejudice on November
17, 2000, because some of the claims were still pending
before the Washington courts at that time and were therefore
unexhausted.

   As noted, the Washington Supreme Court had dismissed all
of Insyxiengmay’s petitions by the end of April 2001. Having
no additional petition in the Washington courts, Insyxiengmay
received approval from the district court to amend his federal
habeas petition, and he resubmitted it to the district court on
February 12, 2002. Insyxiengmay argued in the amended peti-
tion that: (i) the trial court erred in failing to instruct the jury
on the lesser included offense of manslaughter; (ii) the intro-
duction of a non-testifying co-defendant’s statement implicat-
3814                INSYXIENGMAY v. MORGAN
ing Insyxiengmay violated the Confrontation Clause; (iii) the
trial court violated his constitutional rights when it denied his
motion to reopen to permit him to testify; (iv) his constitu-
tional rights were violated when he and his counsel were
excluded from a critical stage of trial (the in camera hearing),
and when his counsel was barred from discussing the exis-
tence of the informant with him; (v) the testimony of the
state’s prime witness pursuant to a coercive plea agreement
violated his right to a fair trial and due process; and (vi) his
Sixth Amendment rights were violated when the polygraph
evidence was excluded at trial. The district court adopted the
magistrate’s report and recommendation, and dismissed the
petition with prejudice on the ground that claims 1, 2, and 6
were procedurally barred and claims 3 through 5 failed on the
merits. The court dismissed the first claim on the ground that
it was presented to the Washington Supreme Court as an issue
of state law, not as a matter of federal law. The second and
sixth claims were dismissed on the ground that they were not
raised either on direct appeal or in the first PRP. The court
made no mention of the second PRP. On the merits, the court
rejected the third, fourth, and fifth claims on the ground that
Insyxiengmay had not shown that the Washington Court of
Appeals’ ruling was contrary to, or involved an unreasonable
application of, clearly established federal law, as determined
by the United States Supreme Court, or resulted in a decision
that was based on an unreasonable determination of the facts
in light of the evidence presented to the state courts. Insy-
xiengmay appealed.

   This Court granted a Certificate of Appealability on two
questions: one, whether the district court erred in ruling that
three of Insyxiengmay’s claims were procedurally barred, and
two, whether the in camera hearing violated Insyxiengmay’s
constitutional rights.

II.    STANDARD OF REVIEW

   Because Insyxiengmay’s application for habeas relief was
filed after the effective date of the Antiterrorism and Effective
                    INSYXIENGMAY v. MORGAN                 3815
Death Penalty Act of 1996 (“AEDPA”), Pub. L. No. 104-132,
110 Stat. 1214 (1996), our review is governed by AEDPA.
Woodford v. Garceau, 538 U.S. 202, 210 (2003); Gill v.
Ayers, 342 F.3d 911, 917 (9th Cir. 2003). “Under AEDPA,
[this court] may only disturb a state court’s determinations of
law if they were ‘contrary to’ or ‘involved an unreasonable
application of’ clearly established federal law as determined
by the United States Supreme Court.” Wade v. Terhune, 202
F.3d 1190, 1195 (9th Cir. 2000) (citations omitted). In consid-
ering potential state court error, this court looks to the “last
reasoned decision of the state court as the basis of the state
court’s judgment.” Franklin v. Johnson, 290 F.3d 1223, 1233
n.3 (9th Cir. 2002).

   Subject to those limitations, we review de novo the district
court’s denial of a petition for habeas corpus. Dubria v. Smith,
224 F.3d 995, 1000 (9th Cir. 2000) (en banc). Additionally,
“the district court’s application of AEDPA, as well as its con-
clusion that the standards set forth in AEDPA are satisfied, is
a mixed question of law and fact which we review de novo.”
Lambert v. Blodgett, 393 F.3d 943, 965 (9th Cir. 2004) (citing
Pullman-Standard v. Swint, 456 U.S. 273, 289 n.19 (1982)).
Thus, the court reviews de novo “a district court’s decision to
dismiss a habeas petition for procedural default.” Vang v.
Nevada, 329 F.3d 1069, 1072 (9th Cir. 2003).

III.   DISCUSSION

A.     Procedural Default

   The State argues that Insyxiengmay’s amended petition
contains claims that were procedurally barred in the Washing-
ton state courts. It contends that Insyxiengmay is precluded
from pursuing any of the claims he raised in the second PRP,
including claims one, two, and six of his federal petition,
because those claims were not timely filed with the state
courts. The State also asserts that even if those claims were
3816                INSYXIENGMAY v. MORGAN
timely filed, they were never fairly and fully presented to the
Washington Supreme Court. Insyxiengmay disagrees.

   The Washington courts dismissed Insyxiengmay’s second
PRP on the ground that it was filed one day after the statute
of limitations expired. Insyxiengmay now challenges the pro-
cedural rule that Washington used to determine when a plead-
ing or other matter from a pro se prisoner is deemed “filed.”

   The “trigger date” by which Insyxiengmay was required to
file his second PRP was June 17, 2000, a Saturday. Under
Washington law, that date was automatically extended to
Monday, June 19, 2000. See Wash. Rev. Code § 1.12.040;
Wash. R. App. P. 18.6. Because Insyxiengmay signed the sec-
ond PRP on Sunday, June 18, 2000, and gave it to a prison
official for filing, and the clerk’s office received it on Tues-
day, June 20, 2000, we may reasonably conclude that it was
delivered to the prison official no later than Monday, June 19,
2000. Insyxiengmay argues that at the time he delivered his
petition the rule in Washington regarding the date on which
a prisoner’s pro se petition is deemed filed was not clear, con-
sistently applied, or well-established. We agree.

   [1] State courts may decline to review a claim based on a
procedural default. Wainwright v. Sykes, 433 U.S. 72 (1977).
Federal courts hearing habeas petitions may not review state
convictions, even for federal constitutional claims, if the state
court judgment procedurally barring the petitioner’s claims
rests on an “independent and adequate” state law ground.
Coleman v. Thompson, 501 U.S. 722, 729 (1991). Procedural
default, a particular type of adequate and independent state
ground, “applies to bar federal habeas review when the state
court has declined to address the petitioner’s federal claims
because he failed to meet state procedural requirements.”
McKenna v. McDaniel, 65 F.3d 1483, 1488 (9th Cir. 1995).
Procedural default is an affirmative defense, and the state has
the burden of showing that the default constitutes an adequate
and independent ground. Vang, 329 F.3d at 1073; Bennett v.
                    INSYXIENGMAY v. MORGAN                  3817
Mueller, 322 F.3d 573, 585-86 (9th Cir. 2003), cert. denied,
540 U.S. 938 (2003). Thus, it is the law of this circuit that the
ultimate burden is on the State, not the petitioner, to show that
a procedural state bar was clear, consistently applied, and
well-established at the time the party contesting its use failed
to comply with the rule in question. See id. at 583.

   Insyxiengmay contends that in 2000, when he filed his sec-
ond PRP, the date of filing rule with respect to pleadings,
appeals or petitions from pro se prisoners was not clear, con-
sistently applied, or well-established in Washington and there-
fore that his failure to comply with the rule does not constitute
an adequate and independent state ground. See Coleman, 501
U.S. at 729 (stating a state procedural rule must be adequate
and independent of federal law in order to bar federal habeas
review); Thomas v. Goldsmith, 979 F.2d 746, 749 (9th Cir.
1992) (same). He avers that it was unclear in 2000 whether
pro se prisoners’ documents were deemed “filed” when they
were received by the clerk’s office or whether the mailbox
rule applied, and they were deemed “filed” when they were
delivered to prison officials for mailing.

   Insyxiengmay points to two contemporaneous cases in
which Washington appellate courts came to differing conclu-
sions about the applicability of the mailbox rule, and thus
about what date is properly deemed the date of filing with
respect to pro se prisoners. He further points to the disagree-
ment on that question in the recent Washington Supreme
Court case resolving the dispute adversely to his position.
Compare State v. Hurt, 27 P.3d 1276 (Wash. Ct. App. Div. III
2001) (holding that the mailbox rule applies to pro se prison-
er’s filings), with In re Carlstad, 80 P.3d 587 (Wash. 2003)
(rejecting the mailbox rule for pro se prisoners’ personal
restraint petitions), and State v. Robinson, 17 P.3d 653 (Wash.
Ct. App. Div. I 2001) (same). See also State v. McLean (In re
Carlstad), 80 P.3d at 593 (Sanders, J., dissenting) (“[T]he
rules governing filing of collateral attacks under RCW
10.73.090, unlike the federal rules considered in Houston[v.
3818               INSYXIENGMAY v. MORGAN
Lack, 487 U.S. 266 (1988)] . . . are not as clear and unambig-
uous in precluding adoption of the mailbox rule . . .”).

   [2] We agree with Insyxiengmay that, when he filed his
second personal restraint petition in 2000, it was unclear
whether Washington applied the mailbox rule to pro se pris-
oner filings, and thus whether the petition was deemed filed
when Insyxiengmay delivered it to the prison official. In
1988, the United States Supreme Court adopted the mailbox
rule for pro se prisoners litigating in federal courts. Houston,
487 U.S. at 266. By 2000, many states had followed the fed-
eral lead. See, e.g., Mayer v. State, 908 P.2d 56 (Ariz. 1995)
(adopting the mailbox rule); In re Jordan, 840 P.2d 983 (Cal.
1992) (same); Haag v. State, 591 So. 2d 614, 615-618 (Fla.
1992) (same); Commonwealth v. Hartsgrove, 553 N.E.2d
1299 (Mass. 1990) (same); Smith v. Pennsylvania Bd. of
Prob. & Parole, 683 A.2d 278 (Pa. 1996) (same). But see,
e.g., Hamel v. State, 1 S.W.3d 434 (Ark. 1999) (refusing to
adopt the mailbox rule); Carr v. State, 554 A.2d 778 (Del.
1989) (same). Had Insyxiengmay filed his petition in a federal
court, there is no doubt that he would have had the benefit of
the mailbox rule. See Houston, 487 U.S. at 266. Washington,
however, had neither expressly adopted nor expressly rejected
the mailbox rule in 2000. Critically, the State has offered no
case or other relevant legal authority, stating when under that
state’s law, as of 2000, pro se prisoners’ documents were
deemed filed. All the cases cited by the State respond to gen-
eral challenges to the statute of limitations, Wash. Rev. Code
§ 10.73.090, not to the question when a pro se prisoner’s doc-
uments were considered “filed.” Finally, the State offered no
evidence of any kind that in 2000 the Washington clerks of
court either deemed pro se prisoner petitions filed when they
were delivered to prison officials or only when they were
received in the clerk’s office. Nor did it offer any evidence as
to the practice of the Washington courts in accepting or reject-
ing pleadings from pro se prisoners that were delivered to
prison officials by the filing date but were not received until
afterwards in the clerk’s office.
                       INSYXIENGMAY v. MORGAN                         3819
   [3] The existence of the federal policy applying the mail-
box rule to pro se prisoners’ filings and the use of the mailbox
rule by numerous other states, the absence of any case on that
question in the Washington appellate courts and the absence
of any evidence as to the practice of the Washington courts
and their various clerks left the question of the applicability
of the mailbox rule uncertain in 2000. Additionally, the fact
that two divisions of the Washington court of appeals came to
opposing conclusions about the existence of the mailbox rule
for pro se prisoners’ filings just a few months following the
filing of Insyxiengmay’s second PRP, ultimately necessitating
a 2003 Washington Supreme Court opinion on the matter,
demonstrates that considerable doubt existed as to whether the
mailbox ruled applied at the time of the filing of Insyxieng-
may’s petition. Thus, the State has not met its burden of
showing that Washington’s procedural rule establishing the
date of filing for pro se prisoners as the date on which the
document is received in the clerk’s office rather than the date
on which it is received by prison officials, was clear, consis-
tently applied, and well-established.4 Bennett, 322 F.3d at
583. Accordingly, claims one, two, and six are not procedur-
ally barred.

B.    Exhaustion

   [4] The State contends that even if the claims in the second
PRP are not procedurally barred, they were not properly pre-
sented to the Washington Supreme Court and are therefore
unexhausted. Under AEDPA, a federal habeas petitioner must
exhaust his claims in state court before coming to federal
court. See 28 U.S.C. § 2254(b)(1)(A). The exhaustion doc-
trine requires a petitioner to provide the state courts with one
  4
    Cockett v. Ray, 333 F.3d 938 (9th Cir. 2003), is not to the contrary. In
that case, unlike ours, the state met its burden of proving the existence of
a procedural bar. The state in that case pointed to two earlier cases in
which this Court had held that the procedural rule at issue was clear, con-
sistently applied, and well-established. Id. at 943.
3820                INSYXIENGMAY v. MORGAN
full opportunity to rule on his federal habeas claims before
presenting those claims to the federal courts. See O’Sullivan
v. Boerckel, 526 U.S. 838, 844-45 (1999) (requiring petition-
ers to give state courts “a fair opportunity to act on their
claims,” that is, “one full opportunity to resolve any constitu-
tional issues by invoking one complete round of the State’s
established appellate review process” (emphasis in original));
Picard v. Connor, 404 U.S. 270, 275 (1971).

   [5] Exhaustion is determined on a claim-by-claim basis.
“Only individual claims, and not the application containing
those claims, can be procedurally defaulted under state law”
pursuant to the adequate and independent state ground doc-
trine. Artuz v. Bennett, 531 U.S. 4, 9 (2000) (emphasis in orig-
inal). A petitioner can satisfy exhaustion by either: (1) fairly
and fully presenting each federal claim to the state’s highest
court or (2) showing that there is no state remedy available.
See Johnson v. Zenon, 88 F.3d 828, 829 (9th Cir. 1996). A
petitioner fairly and fully presents a claim to the state court
for purposes of satisfying the exhaustion requirement if he
presents the claim: (1) to the proper forum, see 28 U.S.C.
§ 2254(c), (2) through the proper vehicle, see Castille v. Peo-
ples, 489 U.S. 346, 351 (1989), and (3) by providing the
proper factual and legal basis for the claim, see Weaver v.
Thompson, 197 F.3d 359, 364 (9th Cir. 1999). A petitioner
must alert the state courts to the fact that he is asserting a fed-
eral claim in order to fairly and fully present the legal basis
of the claim. See Duncan v. Henry, 513 U.S. 364, 365-66
(1995); Lyons v. Crawford, 232 F.3d 666, 668 (9th Cir. 2000),
as modified by 247 F.3d 904 (9th Cir. 2001). In this circuit,
the petitioner must make the federal basis of the claim explicit
either by specifying particular provisions of the federal Con-
stitution or statutes, or by citing to federal case law. See
Lyons, 232 F.3d at 668, 670. While the petitioner must refer
to federal law in state court explicitly, exhaustion is satisfied
once the petitioner makes that explicit reference even if the
petitioner relies predominantly on state law before the state
                   INSYXIENGMAY v. MORGAN                  3821
courts. See Jones v. Smith, 231 F.3d 1227, 1231 (9th Cir.
2000).

   The State argues that Insyxiengmay did not at any time
fairly and fully present the three claims he now appeals to the
Washington Supreme Court. It contends that he presented
claim one on direct appeal, but that he presented it as a matter
of state, not federal, law. It further argues that to the extent
that he raised the three claims in his second PRP, they were
not fairly and fully presented because they were not contained
in the body of his brief, but in a separate attachment, the
Appendix. The State argues that Washington law prohibits
incorporation of issues by reference.

   Following the denial of his second PRP by the Washington
Court of Appeals on the ground that it was not timely filed,
Insyxiengmay filed a motion for discretionary review in the
Washington Supreme Court. In that motion, he presented the
state supreme court with all three claims in an appendix which
consisted of a full copy of his second PRP. The body of the
motion dealt with the court of appeals’ dismissal on the
ground of timeliness. The appendix contained, inter alia,
Insyxiengmay’s arguments regarding the three claims that the
state contends are not exhausted. All three arguments con-
tained the requisite references to the pertinent provisions of
the United States Constitution. Thus, Insyxiengmay clearly
presented all three claims as federal issues to the Washington
Supreme Court.

   [6] The State argues that, because Insyxiengmay’s discus-
sion of the three claims does not appear in the body of the
motion, Washington law prohibits their consideration. It
asserts that Washington courts do not permit “incorporation”
in motions, briefs, or petitions of material contained in the
appendices to those documents. All the cases cited by the
State in support of its argument involve briefs or other filings
that raise issues by incorporation by reference of another doc-
ument not before the appellate court, generally trial memo-
3822                   INSYXIENGMAY v. MORGAN
randa. See, e.g., State v. Kalakosky, 852 P.2d 1064, 1072 n.18
(Wash. 1993). In other words, those cases prohibit incorpora-
tion of material that has not been filed with the court itself.
See id. (“Only issues . . . argued to the appellate court are con-
sidered on appeal.”). Here, in the appendix filed in the state
supreme court along with his motion, Insyxiengmay presented
extensive argument in support of all three claims as well as
citations to the requisite authority and to relevant parts of the
record. Accordingly, the claims were fairly and fully pres-
ented to the Washington Supreme Court.5

C.     In Camera Hearing

   [7] Insyxiengmay challenges the trial court’s decision to
exclude him and his attorney from an in camera hearing
regarding his request to be advised of the identity of the confi-
dential informant and of any information the informant pos-
sessed that might be relevant to his defense. A defendant has
a right guaranteed by the Confrontation Clause of the Sixth
Amendment and the Due Process Clause of the Fifth Amend-
ment to be present at every critical stage of the proceedings.
See Illinois v. Allen, 397 U.S. 337, 338 (1970) (discussing
confrontation clause); Faretta v. California, 422 U.S. 806,
819 n.15 (1975) (discussing due process clause). “Few rights
are more fundamental than that of an accused to present wit-
nesses in his own defense.” Taylor v. Illinois, 484 U.S. 400,
417 n.23 (1988) (citation omitted).
  5
    Indeed, we question whether in order to exhaust the three claims it was
even necessary for Insyxiengmay to file an appendix with the Washington
Supreme Court discussing their merits. Because in his motion Insyxieng-
may asked the Washington Supreme Court to allow the claims to proceed
in the court of appeals, and the court declined the request, thus barring him
from presenting the claims for review either to the court of appeals or the
supreme court, any further duty to exhaust was excused. Under the cir-
cumstances, presenting any argument on the merits would have been, and
was, futile.
                   INSYXIENGMAY v. MORGAN                      3823
   Because the trial court permitted only the witness (the law
enforcement officer to whom the confidential informant
reported) and the prosecutors to be present at the hearing and
did not allow defense counsel to submit questions for the wit-
ness, the Washington Court of Appeals concluded that
“[f]ailing to notify the defendant of an in camera proceeding
or to permit the defense counsel to submit questions to be
asked of the informant is a violation of basic Sixth Amend-
ment due process,” citing State v. Smith, 677 P.2d 100, 105
(Wash. 1984). On this appeal, the State has not questioned the
correctness of the state court of appeals’ determination that
Insyxiengmay’s Sixth Amendment right was violated. Instead,
it relies exclusively on that court’s prejudice ruling.

   No court that has reviewed this case has disagreed that the
exclusion of the defense from the in camera hearing violated
Insyxiengmay’s Sixth Amendment rights. The district court
dismissed Insyxiengmay’s claim, however, “because peti-
tioner [ ] failed to show [the confidential informant] had any
information pertinent to petitioner’s case.” In doing so, the
court failed to recognize that the facts in the record before it
gave rise to the clear inference that the informant possessed
material information. More important, it erroneously failed to
afford Insyxiengmay an evidentiary hearing.

  [8] We have previously outlined the procedure for district
courts to follow when determining whether an evidentiary
hearing is warranted post-AEDPA:

    Under the amended statutory scheme, a district court
    presented with a request for an evidentiary hearing
    . . . must determine whether a factual basis exists in
    the record to support the petitioner’s claim. If it does
    not, and an evidentiary hearing might be appropriate,
    the court’s first task in determining whether to grant
    an evidentiary hearing is to ascertain whether the
    petitioner has “failed to develop the factual basis of
    a claim in State court.” If so, the court must deny a
3824                   INSYXIENGMAY v. MORGAN
      hearing unless the applicant establishes one of the
      two narrow exceptions set forth in section
      2254(e)(2)(A) & (B). If, on the other hand, the appli-
      cant has not “failed to develop” the facts in state
      court, the district court may proceed to consider
      whether a hearing is appropriate, or required under
      Townsend [v. Sain, 372 U.S. 293 (1963)].

Baja v. Ducharme, 187 F.3d 1075, 1078 (9th Cir. 1999). In
Townsend, the Supreme Court concluded that a defendant is
entitled to a federal evidentiary hearing on his factual allega-
tions if:

      (1) the merits of the factual dispute were not
      resolved in the state hearing; (2) the state factual
      determination is not fairly supported by the record as
      a whole; (3) the fact-finding procedure employed by
      the state court was not adequate to afford a full and
      fair hearing; (4) there is a substantial allegation of
      newly discovered evidence; (5) the material facts
      were not adequately developed at the state-court
      hearing; or (6) for any reason it appears that the state
      trier of fact did not afford the habeas applicant a full
      and fair fact hearing.

372 U.S. at 313. Assuming that the petitioner has not failed
to develop his claim and can meet one of the Townsend fac-
tors, “[a]n evidentiary hearing on a habeas corpus petition is
required whenever petitioner’s allegations, if proved, would
entitle him to relief.” Turner v. Marshall, 63 F.3d 807, 815
(9th Cir. 1995) (citations omitted).6
  6
    Although it appears that in order for a petitioner to show that he has
“not failed to develop his claim” he will in most cases have had to satisfy
one of the Townsend factors, we recognize that our precedent requires that
after meeting the “has not failed” requirement, the petitioner must proceed
to satisfy Townsend. However, in such instances, meeting the second part
of the test will ordinarily be only a formality.
                    INSYXIENGMAY v. MORGAN                  3825
   The petitioner’s allegations need only amount to a color-
able claim. See Beaty v. Stewart, 303 F.3d 975, 993 (9th Cir.
2002) (citing Townsend, 372 U.S. at 313); see also, Phillips
v. Woodford, 267 F.3d 966, 973 (9th Cir. 2001) (“Where a
petitioner raises a colorable claim [to relief], and where there
has not been a state or federal hearing on this claim, we must
remand to the district court for an evidentiary hearing.”). In
sum, for a post-AEDPA petitioner to receive an evidentiary
hearing in federal court, he must first show that he has not
failed to develop the factual basis of the claim in the state
courts: if he has failed, he must meet one of the two narrow
exceptions stated in the statute. See 28 U.S.C. § 2254(e)(2)(A)
- (B). Then he must meet one of the Townsend factors and
make colorable allegations that, if proved at an evidentiary
hearing, would entitle him to habeas relief.

   [9] Insyxiengmay did not “fail to develop” the factual basis
for his Sixth Amendment claim in the state courts. Under
AEDPA, “a failure to develop the factual basis of a claim is
not established unless there is a lack of diligence, or some
greater fault, attributable to the prisoner or the prisoner’s
counsel.” Williams v. Taylor, 529 U.S. 420, 432 (2000) (citing
Baja, supra, with approval). Fault cannot be attributed to
Insyxiengmay because both he and his counsel were barred
from the in camera hearing, and the court prohibited counsel
from informing him of it, as well as of the existence of the
confidential informant.

   Fault also cannot be attributed to Insyxiengmay’s counsel.
Counsel attempted to obtain information regarding the State’s
confidential informant and his knowledge of the facts. The
trial court precluded him from speaking with his client about
the informant, excluded him from the hearing, and refused to
allow him to submit questions for the court to ask the infor-
mant. Thus, neither Insyxiengmay nor his counsel failed to
develop the factual basis for the claim. Because, through no
fault of his own, Insyxiengmay was not afforded a full and
fair hearing by the state court, he is entitled to an evidentiary
3826                  INSYXIENGMAY v. MORGAN
hearing if he has presented a colorable claim that he was prej-
udiced by the Sixth Amendment violation found by the Wash-
ington courts. See Baja, 187 F.3d at 1078.

   [10] Insyxiengmay alleges that the informant possessed
“information substantial to his defense.” At the in camera
hearing, Deputy Cassio described having a “working relation-
ship” with informant Prak, who had provided information
“with regards to the activities of different members of” the
defendants’ gang. Although it is unclear precisely what the
extent of the relationship was between the informant and the
deputy, and what information the informant may have con-
tributed to the shootings investigation, apparently the relation-
ship was close enough that the deputy felt compelled to falsify
his police report to exclude any reference to Prak. It was evi-
dent from the in camera hearing that the informant had spent
time with all of the defendants after the shootings and pre-
sumably had conveyed information from them regarding the
criminal occurrence to Deputy Cassio. Indeed, the informant
was with Insyxiengmay’s co-defendant at the time of his
arrest. Prak knew both Insyxiengmay and the others involved
in the shootings well and may also have obtained information
from other gang members regarding the criminal conduct at
issue. In short, the confidential informant was an individual
who was in a position to provide highly relevant information
to the defense.

   [11] Given all the circumstances, it was unreasonable for
the state courts to assume that the informant did not possess
information that could have materially benefitted the defen-
dant. The facts suggest otherwise. Insyxiengmay has alleged
a colorable claim of prejudice — a claim that he was pre-
cluded from developing at the state-court hearing. He is enti-
tled to an evidentiary hearing.7
  7
   Insyxiengmay was pro se in the district court. On appeal, we appointed
counsel. Counsel filed Motions to Enlarge Record on Appeal that included
an affidavit recently obtained from confidential informant Prak. The affi-
davit sets forth exculpatory material of which Prak had knowledge at the
time of the in camera hearing. Because we may reverse without even con-
sidering the affidavit, we deny the motions.
                   INSYXIENGMAY v. MORGAN                3827
IV.   CONCLUSION

   With respect to the manslaughter instruction (claim 1), the
admission of the guilty plea (claim 2), and the exclusion of
the adverse polygraph evidence (claim 6), we reverse because
the claims are exhausted and are not procedurally barred. We
remand those claims to the district court for a resolution on
the merits. We also remand the Sixth Amendment claim to the
district court for an evidentiary hearing on the question of
prejudice.

  REVERSED AND REMANDED FOR FURTHER
PROCEEDINGS CONSISTENT WITH THIS DECI-
SION.
