FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA, 

No. 07-10289 Plaintiff-Appellee,

D.C. No.

v.  CR-98-00198-HG

JANICE L. PEREZ,

OPINION Defendant-Appellant. 

Appeal from the United States District Court

for the District of Hawaii

Helen Gillmor, District Judge, Presiding

Argued and Submitted

September 25, 2007—San Francisco, California

Filed May 16, 2008

Before: John R. Gibson,* Marsha S. Berzon, and

Carlos T. Bea, Circuit Judges.

Opinion by Judge Bea

*The Honorable John R. Gibson, Senior United States Circuit Judge for

the Eighth Circuit, sitting by designation. 

5719
COUNSEL

Peter C. Wolf, Federal Public Defender, Matthew C. Winter,

Assistant Federal Public Defender, Honolulu, Hawaii, for

defendant-appellant Janice Perez. 

Edward H. Kubo, Jr., United States Attorney, Tracy A. Hino,

Assistant United States Attorney, Honolulu, Hawaii, for

plaintiff-appellee United States of America.

OPINION

BEA, Circuit Judge: 

We are called upon in this case to decide whether a person

on supervised release has a right to cross-examine the laboratory technician who tested a urine sample containing an illegal drug, where: (1) the test report itself stated the sample was

“dilute”

1—meaning the urine sample had been combined with

another liquid at some point before or during the testing; (2)

the evidence presented showed the person on supervised

release did not have an opportunity herself to dilute nor add

1

“Dilute” means to “to make thinner or more liquid by admixture.”

Merriam-Webster’s Online Dictionary http://www.merriam-webster.com

(last visited April 23, 2008). 

5722 UNITED STATES v. PEREZ
a substance to the sample; and (3) the result of the urinalysis

was critical to support a finding that the person on supervised

release had possessed or used illegal drugs. Because the illegal drug found in the tested sample could only have come

from Perez’s urine, an added substance, or another liquid, and

because the validity of the urinalysis was the critical issue in

determining whether Perez had used cocaine, we reverse the

district court and hold the person on supervised release had a

right to cross-examine the technician who handled and tested

the sample. Absent such cross examination, the urinalysis

should not have been admitted, and the consequent revocation

of supervised release cannot stand. 

We caution that this is an unusual case with unusual facts

and should not be taken out of context. We do not hold that

a releasee always has a right to cross-examine the technician

who tested a urine sample. This is not a case where other evidence was offered in support of revocation, such as illegal

drugs discovered in the possession of the releasee. Nor is this

a case where multiple urine samples each tested positive.

Here, the urinalysis report was the critical piece of evidence

presented in support of the charge that Perez tested positive

for cocaine. Although urinalysis results may often be sufficiently reliable evidence that the opportunity for crossexamination is unnecessary for due process purposes, see

United States v. Martin, 984 F.2d 308, 313-14 (9th Cir. 1993),

here the report itself showed the sample had been adulterated.

Given that the sample was uncontestably adulterated, the test

results were in fact ineluctably unreliable.

I

In 1998, Janice Perez pleaded guilty to bank robbery in violation of 18 U.S.C. § 2113(a). She was sentenced to a term of

seventy-seven months imprisonment and three years supervised release. 

Perez’s term of supervised release commenced on March 8,

2007. Her release conditions required Perez to “follow

UNITED STATES v. PEREZ 5723
instructions of the probation officer” and to abstain from

using alcohol or drugs not prescribed for her. 

On March 15th, Perez wished to travel to Maui to see her

gravely ill brother, who was on life support. After verifying

her brother’s condition, Perez’s probation officer, Derek Kim,

permitted her to go to Maui, but directed her to come to his

office upon her return, provide her travel itinerary and submit

to a drug test. 

When Perez returned, she went to the probation office and

submitted her travel itinerary, but left without taking a drug

test. Kim telephoned Perez to ask why she did not stay to be

tested; Perez told him she forgot because she was upset after

learning her brother had been taken off life support that day

and had passed away. 

Kim already knew about her brother’s death, and testified,

“so when she told me she forgot because she was upset, you

know, I didn’t think anything of it other than the fact that,

well, I could see that that’s conceivable.” Kim did not ask

Perez to come back into the office that day for a drug test.

Instead, Kim instructed Perez to come by the office for a drug

test the following day (March 20), which she did. That test

established there were no illegal drugs in Perez’s system. 

Kim then directed Perez to report to Freedom Recovery

Services (“FRS”), the outside contractor the probation office

uses to monitor persons on supervised release, to undergo

FRS’s orientation. 

On March 21st, the day after she passed a urine test at the

probation office, Perez duly reported to FRS. Even though

Kim had not directed her to get tested, Perez voluntarily submitted to another urinalysis. 

Mrs. Billee Schnaible, who worked at FRS, testified she

observed Perez give the urine sample; neither Perez nor the

5724 UNITED STATES v. PEREZ
sample were ever out of Schnaible’s sight. The bathroom used

was specially equipped with mirrors allowing Mrs. Schnaible

to observe Perez and ensure she did not have an opportunity

to adulterate the sample. Mrs. Schnaible testified Perez did

not adulterate or “dilute” the sample. 

According to a dip-stick test, the sample tested positive for

cocaine metabolites. Perez protested vigorously saying, “I just

tested at my PO’s [Probation Officer’s] yesterday and I’m

clean, I’m clean, it can’t be.” Mrs. Schnaible testified that

their usual practice would have been to conduct another test,

but she did not remember collecting a second urine sample or

doing a second test.2

Later, Dennis Schnaible, another FRS staff member, testified that after Perez protested, Mrs. Schnaible “got another

testing device, a new one, and dipped it into the same urine.

And the results were the same.” Mr. Schnaible then assured

the lid was on tight so the sample would not leak during shipping, watched Mrs. Schnaible fill out a chain of custody form,

and sent Perez’s urine sample to Scientific Testing Laboratories, Inc. (“STLI”) in Virginia.3

 STLI is the designated testing

laboratory for U.S. Probation and Pretrial Services. According

to Mr. Schnaible, no second urine sample was taken from

Perez. 

That same day, on March 21st, after Perez had been to

FRS, she returned to the probation office. Kim was out of

town, but Perez asked another probation officer named Robin

DeMello to take a urine sample and test it for her; DeMello

refused. 

2There was no evidence one way or the other as to whether either of the

Schnaibles adulterated the sample, although both testified and were crossexamined. 

3No one suggests either Schnaible adulterated the urine sample. 

UNITED STATES v. PEREZ 5725
Mr. Schnaible testified the testing method used by FRS is

not always reliable, which is why FRS uses the laboratories

at STLI. He recalled one time when the method used by FRS

resulted in four samples testing positive for drugs, but when

those samples were sent to STLI, three of them tested negative. 

The STLI report showed Perez’s sample tested positive for

cocaine. It also recorded abnormally low readings for the

presence of creatinine (a breakdown product of creatine, an

important part of muscle, produced by one’s kidneys) and the

urine’s specific gravity. The report stated the following:

“Specimen Validity Status: DILUTE.” Perez objected that the

STLI urinalysis report was hearsay, but it was nonetheless

introduced into evidence. No STLI employee testified regarding the urinalysis report. 

Also over Perez’s hearsay objection, Kim testified the low

creatine and specific gravity values meant that “rather than

drinking tons of water, or other types of liquid, that [the people at STLI] actually believe a dilute, meaning that it was a

liquid which included some urine.” That the sample was

diluted means that it had been adulterated. It not only contained Perez’s urine, it also contained another unknown liquid

that had been combined with the urine. Kim then speculated

that someone could produce a dilute sample by using a hidden

container to pour adulterated urine into the sample cup. 

Perez argued to the district court the urinalysis result must

be rejected because the sample had been adulterated. Perez

contended she could not have adulterated the sample because

she had been under the vigilant eye of Billee Schnaible when

she gave the sample. She also contended her adamance she

had not taken drugs and her multiple attempts to provide an

additional sample that same day—at both FRS and then at the

probation office—cast doubt on the accuracy of the urinalysis.

The government responded that the sample was still available

for retesting. 

5726 UNITED STATES v. PEREZ
The district court rejected Perez’s argument, concluding

Perez had no credibility because of a long history of dishonesty. The district court made it clear its adverse credibility

determination was not based on any evidence Perez diluted

her own urine; the only grounds cited by the district court

were some vague references to prior bad acts of the defendant. It is noteworthy there was no evidence introduced at the

revocation hearing of any such prior bad acts. Likewise, there

was no statement by the district court that anything about

Perez’s demeanor or manner of testifying caused her to lose

credibility in the district court’s eyes. 

The district court found Perez guilty of both charges in the

Request for Course of Action, specifically finding that Perez:

(1) “refused to submit to drug testing at the Probation Office

on 3/19/2007 as instructed on 3/15/2007”; and (2) Perez’s

“urine specimen submitted on 3/21/2007 tested positive for

cocaine.” 

II

We have jurisdiction under 28 U.S.C. § 1291 and 18 U.S.C.

§ 3742. We review the district court’s decision to revoke a

term of supervised release for an abuse of discretion. United

States v. Verduzco, 330 F.3d 1182, 1184 (9th Cir. 2003).

Whether a defendant has received due process at a revocation

proceeding is a mixed question of law and fact we review de

novo. See United States v. Havier, 155 F.3d 1090, 1092 (9th

Cir. 1998). “A due process violation at a revocation proceeding is subject to harmless error analysis.” Verduzco, 330 F.3d

at 1184 (internal quotation marks omitted). We reverse. 

III

A district court may revoke a term of supervised release

only if it “finds by a preponderance of the evidence that the

defendant violated a condition of supervised release.” 18

U.S.C. § 3583(e)(3); see also Morrissey v. Brewer, 408 U.S.

UNITED STATES v. PEREZ 5727
471, 484 (1972) (holding a revocation cannot stand on “erroneous information”); United States v. Martin, 984 F.2d 308,

310 (9th Cir. 1993) (holding a revocation of supervised

release must be “based on verified facts”). Although this is a

lower standard than the “beyond a reasonable doubt” standard

required for a criminal conviction, there must still be credible

evidence the releasee actually violated the terms of supervised

release. 

A.

[1] With regard to the first count—that Perez “refused” to

submit to drug testing on March 19th—there is no evidence

Perez intentionally refused to be tested. True enough, Perez

was ordered to submit to drug testing after her return from

Maui, and she did not do so. The charge, however, was not

“failure” to submit to testing, the charge was “refusing” to

submit to testing. The only evidence regarding Perez’s refusal

was in her favor. She told Kim she forgot to stay for drug testing on March 19th because her brother died that day. Kim

testified he verified the brother’s death and consequently

“thought nothing” of her failure to stay for drug testing when

she dropped off her travel itinerary. He accepted her explanation as “conceivable.” He did not ask her to come back into

the office that day, and she did not refuse to do so. Further,

she submitted to a drug test the very next day, and tested negative for the presence of drugs. Accordingly, there was no evidence from which the trial court could find it was more

probable than not Perez “refused” to submit to drug testing.

B.

With regard to the second count—that Perez’s urine specimen submitted on 3/21/2007 tested positive for cocaine—

although the admission of a urinalysis without the opportunity

for cross-examination is not necessarily error, given the particular facts of this case, the admission of this evidence with5728 UNITED STATES v. PEREZ
out allowing Perez to cross-examine the laboratory technician

was error. 

[2] Admission of hearsay evidence in revocation of supervised release proceedings is governed by the Fifth Amendment right to due process. See United States v. Hall, 419 F.3d

980, 985 & n.4 (9th Cir. 2005). A “releasee is guaranteed the

right to confront and cross-examine adverse witnesses at a

revocation hearing, unless the government shows good cause

for not producing the witnesses.” Hall, 419 F.3d at 986 (internal quotation marks omitted); see also Fed. R. Crim. P.

32.1(b)(2)(C) (a releasee is entitled to “an opportunity to

appear, present evidence, and question any adverse witness

unless the court determines that the interest of justice does not

require the witness to appear”). 

[3] In Martin, we construed this right “as requiring that a

supervised releasee receive a fair and meaningful opportunity

to refute or impeach the evidence against him in order ‘to

assure that the finding of a [supervised release] violation will

be based on verified facts.’ ” 984 F.2d at 310 (citation omitted) (alterations in original). When evaluating the weight of

the releasee’s right, we examine, inter alia: (1) the importance

of the evidence to the district court’s ultimate findings; (2) the

nature of the facts to be proven by the hearsay; and (3)

whether the releasee had any opportunity to refute the evidence. Id. at 312. 

Perez was consistently denied any opportunity to refute the

urinalysis results. Not only was her request to give another

sample on the same day rejected by FRS and the probation

department, but the district court denied her request to crossexamine the technician. This meant that here, as in Martin,

the releasee had a “virtually complete denial of any opportunity to refute the evidence.” 984 F.2d at 311. 

[4] The evidence established the following undisputed

facts: Perez gave a urine sample. Mrs. Schnaible testified that

UNITED STATES v. PEREZ 5729
it was Perez’s urine that was in the sample sent to STLI for

testing, and also that Perez did not have any opportunity to

adulterate the sample. Given the undisputed evidence in this

record that Mrs. Schnaible was watching Perez the entire

time, it cannot be said it is more likely than not that Perez was

the one who diluted the sample. We also know the FRS testing method was unreliable. Mr. Schnaible so testified when he

noted that previously they had sent four positive samples to

the lab, only to have three of them test negative at STLI. The

fact that FRS’s analyses showed cocaine in the sample does

not preclude the possibility that a foreign substance added at

STLI was the source of the cocaine, given that we know

FRS’s tests are unreliable. 

[5] By the time Perez’s sample was tested at STLI in Virginia, the sample had been diluted with another liquid. We

know this because the urine specific gravity and creatine

levels were low. Under these circumstances, the government’s

offer to re-test the sample did not solve the problem with the

adulteration of the sample. A re-test of the sample might tell

us the foreign substance in the sample and whether it is a substance commonly found in a laboratory, or it might not. What

a re-test will not tell us is: (1) how the foreign substance got

into the sample; (2) who introduced the foreign substance into

the sample; or (3) whether the foreign substance was the

source of the cocaine metabolites. 

[6] Perez had an obvious interest in cross-examining someone from the lab on, inter alia, the results of the report, the

chain of custody of the sample once it arrived at STLI, their

testing methodology, their findings, whether anyone there

could have introduced the foreign substance into the sample,

whether cocaine is stored at the facility, the ratio of the urine

to the other liquid in the sample, the concentration of cocaine

found in the sample, the time cocaine remains in a person’s

system, and the ways in which a sample could become “dilute.” Although Perez had an opportunity to cross-examine

the probation officer, Kim, who spoke to someone at STLI,

5730 UNITED STATES v. PEREZ
Kim did not have personal knowledge regarding anything that

happened at the STLI lab in Virginia. The urinalysis and

Kim’s testimony that someone had attempted to dilute the

sample were the only evidence offered to prove Perez’s guilt.

Thus, Perez had a strong interest in being able to confront the

person who actually handled and tested the sample at STLI

and who wrote the report. 

[7] Balanced against the releasee’s interest in crossexamining a declarant is the government’s interest in not putting the declarant on the stand, including: (1) the expense or

difficulty of getting the witness to the stand; and (2) the reliability of the evidence. Hall, 419 F.3d at 988. Because we

know the evidence was ineluctably unreliable in this case, the

government has a heavy burden to prove it could not have

made the witness available for questioning. The court in Martin held even if there is a significant expense in bringing the

declarant to testify, the government does not get credit for this

factor if it failed to use an available substitute for live testimony, such as “affidavits, depositions, and documentary evidence.” Martin, 984 F.2d at 313. 

The government argues that because the laboratory technician was in Virginia and the hearing was in Hawaii, it would

have been quite time-consuming and expensive to transport

the witness to Hawaii for the hearing. Further, the government

maintains the evidence was reliable because STLI was the

national testing laboratory for the U.S. Probation Offices and

U.S. pretrial offices, which shows it “has extensive experience in this area [and] its reports carry greater indications of

reliability” than other hearsay evidence. Martin, 984 F.2d at

314. All this is true, but the fact remains the sample was

labeled by STLI itself as adulterated. The government could

have offered to allow Perez’s counsel to depose the technician

(including deposing the technician in person, by videoconferencing, or by telephone), or at least offered a detailed

affidavit explaining the areas of possible cross-examination

UNITED STATES v. PEREZ 5731
noted above, which would have cost the government very little. It did neither.4

[8] The district court compounded this error by relying on

Perez’s previous violations to disbelieve Perez’s denials of

culpability, rather than on any evidence that Perez committed

the acts alleged here. There was no evidence Perez herself

diluted the sample. The only evidence in this case that relates

to Perez actually makes it less likely she was the one who

diluted the sample. Mrs. Schnaible testified she observed

Perez give the sample and the sample was never out of Mrs.

Schnaible’s sight from the time Perez first gave the sample to

the time it was sealed and mailed off to STLI. 

[9] Further undercutting the district court’s speculation

about what might have happened, Perez immediately

requested that FRS run another test. When FRS did not take

another urine sample, Perez went straight from FRS back to

the probation office, where she requested the probation office

take another sample. We think it unlikely a guilty party would

seek out scientific confirmation of her guilt. 

A term of supervised release cannot be revoked unless

there is actual evidence the person on supervised release committed the acts alleged in the charging instrument (in this

case, the Request For Course Of Action). See Morrissey, 408

U.S. at 484 (holding a revocation cannot stand on “erroneous

information”); Martin, 984 F.2d at 310 (holding a revocation

of supervised release must be “based on verified facts”). District courts must be cautious not to use the releasee’s prior

crimes to find the releasee violated the terms of supervised

release where there is no reliable evidence the releasee did so.

4We do not decide that this substitute for cross-examination would have

satisfied due process. That determination would depend on what the affidavit said, who submitted it, why the possibility of a deposition or television appearance was rejected, and what opportunities were available to

refute the affidavit. See Martin, 984 F.2d at 312-14. 

5732 UNITED STATES v. PEREZ
[10] In criminal trials, evidence of other crimes is generally

not admissible to prove action in conformity therewith. See

Fed. R. Evid. 404(b). Evidence of prior convictions for crimes

of dishonesty is admissible to attack the truthfulness of that

witness, Fed. R. Evid. 609(a), but Perez did not testify. Even

though the rules of evidence do not apply to revocation proceedings, the same logical fallacy exists—you cannot convict

someone of a new offense based solely on their prior bad acts.

It is clear the district court relied solely on prior bad acts by

Perez instead of evidence in this case. For instance, even

though Perez did not testify in this proceeding, at one point

the district court exclaimed, “Her credibility is in the minus

figures [and] If she told me it was daylight, I would go open

the window and check.” 

[11] Finally, the error here could not have been harmless

because the urinalysis was the only actual evidence used to

revoke Perez’s supervised release. See Hall, 419 F.3d at 987

n.5. Accordingly, Perez’s interest in cross-examining the laboratory technician so outweighed the government’s interest in

not producing the witness that the admission of the hearsay

evidence violated her Fifth Amendment constitutional right to

due process. See Martin, 984 F.2d at 314. 

The revocation of Perez’s supervised release is reversed

and judgment is rendered in favor of Perez. If Perez has not

already been released, the district court is instructed to vacate

its finding she violated the terms of supervised release, order

her immediate release from any prison term imposed for the

claimed violation of supervised release, and enter an order in

accordance with this opinion. 

REVERSED.

UNITED STATES v. PEREZ 5733