SUPREME COURT OF ARIZONA

En Banc

STATE OF ARIZONA, ) Arizona Supreme Court 

 ) No. CR-09-0339-PR 

 Appellee, ) 

 ) Court of Appeals 

 v. ) Division One 

 ) No. 1 CA-CR 08-0318 

JOSEPH WESLEY GOMEZ, ) 

 ) Maricopa County 

 Appellant. ) Superior Court 

 ) No. CR2006-166549-001 DT 

 )

 )

 ) O P I N I O N

__________________________________)

Appeal from the Superior Court in Maricopa County 

The Honorable Gary E. Donahoe, Judge

AFFIRMED

________________________________________________________________

Memorandum Decision of the Court of Appeals, Division One

Filed Oct. 29, 2009

AFFIRMED IN PART, VACATED IN PART

________________________________________________________________

TERRY GODDARD, ARIZONA ATTORNEY GENERAL Phoenix

 By Kent E. Cattani, Chief Counsel, 

 Criminal Appeals/Capital Litigation Section

 Julie A. Done, Assistant Attorney General

Attorneys for State of Arizona

BRUCE F. PETERSON, OFFICE OF THE LEGAL ADVOCATE Phoenix

 By Frances J. Gray, Deputy Legal Advocate

Attorneys for Joseph Wesley Gomez

________________________________________________________________

H U R W I T Z, Vice Chief Justice

¶1 The issue before us is whether the Confrontation 

Clause of the Sixth Amendment to the United States Constitution 
2 

is violated when a testifying expert offers an opinion on the 

similarity of DNA profiles prepared by technicians who did not 

testify. We conclude that the expert’s testimony did not 

contravene the Confrontation Clause. 

I. 

¶2 In 2006, Joseph Wesley Gomez was arrested and charged 

with crimes related to a home invasion. Police collected items 

from the crime scene and submitted them, along with a blood 

sample taken from Gomez, to a laboratory. The laboratory 

analyzed DNA from the items and compared the results with the 

DNA from the blood sample. 

¶3 In performing DNA testing and analysis, the laboratory 

used an “assembly line” method that involved seven steps. 

During the first six steps of the process, technicians isolate 

and amplify the DNA and generate profiles. The technicians do 

not interpret data or draw conclusions during these first six 

steps, in which machines are used for every step except the 

initial screening of submitted items for DNA.1

 Various 

                                                           

1

 The evidence is screened initially by a technician for the 

presence of DNA. If DNA is found, it is extracted from the 

evidence and a machine measures its quantity. Copies of 

specific regions of the DNA are then machine generated. 

Machines then separate the DNA so that the alleles may be 

examined and determine which alleles are present. A software 

program processes that data and generates DNA profiles, which 

list the number of alleles present at certain spots within the 

genetic code. Finally, an analyst examines the generated 

profiles and compares them to known profiles. 
3 

technicians involved in the laboratory processes did not testify 

at Gomez’s trial. 

¶4 The State instead called a single witness about the 

DNA testing. That witness, a senior forensic analyst and 

supervisor at the laboratory, testified in detail about the 

laboratory’s operating procedures, standards, and safeguards. 

Although the analyst had not witnessed all of the steps in the 

process, she had checked the technicians’ records for any 

deviations from the laboratory’s protocols. The analyst had 

performed the initial evidence screening and DNA extraction on 

most of the items, and she testified about the chain of custody 

for all items. For each sample, the analyst personally 

performed the final step in the process, interpretation and 

comparison. This step required her to compare the DNA profiles 

generated in the laboratory, and it was the only step involving 

human analysis. 

¶5 The analyst testified that several profiles derived 

from evidence at the crime scene “matched” the profile obtained 

from Gomez’s blood sample.2

 The data from the testing process 

were not introduced into evidence as exhibits. 

                                                           

2

 The analyst testified that the odds of finding a DNA match 

from someone other than Gomez for the DNA on each piece of 

evidence from the crime scene ranged from one in thirteen 

thousand to one in 1.2 sextillion. 
4 

¶6 Gomez was convicted of the charged felonies. The 

court of appeals affirmed, rejecting Gomez’s argument that the 

expert’s testimony violated the Confrontation Clause. State v. 

Gomez, 1 CA-CR 08-0318 (App. Oct. 29, 2009) (mem. decision). 

¶7 We granted review because the application of the 

Confrontation Clause to expert testimony about DNA profiles is 

an issue of statewide importance likely to recur. We have 

jurisdiction under Article 6, Section 5(3) of the Arizona 

Constitution and A.R.S. § 12-120.24 (2003). 

II. 

¶8 The Sixth Amendment guarantees that “[i]n all criminal 

prosecutions, the accused shall enjoy the right . . . to be 

confronted with the witnesses against him.” U.S. Const. amend. 

VI. The “primary object” of the Confrontation Clause is 

“testimonial hearsay.” Crawford v. Washington, 541 U.S. 36, 53 

(2004). Crawford declined to establish a precise definition of 

“testimonial,” but gave examples such as affidavits, prior 

testimony, depositions, and items contained in “formalized” 

materials. Id. at 51-52. 

¶9 In Melendez-Diaz v. Massachusetts, 129 S. Ct. 2527, 

2532 (2009), the Supreme Court held that expert affidavits 

containing the results of forensic tests prepared for purposes 

of trial were testimonial hearsay. In Melendez-Diaz, analysts 

tested a substance, found it to be cocaine, and signed 
5 

affidavits so affirming. Id. at 2531. The Court found that the 

defendant’s confrontation rights were violated when the State 

used the affidavits to prove that the tested substance was 

cocaine without presenting any of the analysts for crossexamination. See id. at 2532. 

III. 

¶10 Gomez contends that because the laboratory technicians 

who generated the DNA profiles did not testify at his trial, the 

analyst’s testimony violated the Confrontation Clause. In 

assessing Gomez’s argument, it is useful to separate the 

analyst’s testimony into two parts: (1) her testimony regarding 

the laboratory protocols and the generation of the DNA profiles 

and (2) her expert opinion that several of the profiles matched. 

See Pendergrass v. State, 913 N.E.2d 703 (Ind. 2009) (addressing 

Confrontation Clause issues when state presented two witnesses, 

a laboratory supervisor who testified to procedures used in 

generating profiles and a DNA analyst who compared profiles). 

A. 

¶11 Gomez correctly does not argue that the analyst’s 

testimony about her role in the testing process, the 

laboratory’s procedures, and the qualifications of the 

technicians was hearsay. This testimony was based on the 

analyst’s personal knowledge. Rather, Gomez argues that the 
6 

analyst’s testimony about the DNA profiles was hearsay because 

she was not involved in generating those profiles. 

¶12 It is not clear that the data in the machine-generated 

DNA profiles were hearsay statements. In United States v. 

Washington, a divided Fourth Circuit held that printed data from 

a gas chromatograph were not hearsay statements and therefore 

the Sixth Amendment was not offended when the data were 

introduced into evidence without offering the testimony of the 

technicians who operated the machine. 498 F.3d 225, 229-32 (4th 

Cir. 2007). But see id. at 232-35 (Michael, J., dissenting) 

(concluding that data printouts are testimonial hearsay). After 

Melendez-Diaz, the Supreme Court denied certiorari in 

Washington, 129 S. Ct. 2856 (2009), and the Court has not yet 

decided whether machine-generated data are testimonial hearsay. 

Some courts, however, have so held. See, e.g., Commonwealth v. 

Banville, 931 N.E.2d 457, 466 (Mass. 2010) (involving DNA 

profiles); see also Washington, 498 F.3d at 233 (Michael, J., 

dissenting) (collecting cases to show that courts “consistently 

consider computer-generated assertions of fact as hearsay 

statements”). We assume without deciding that the machinegenerated DNA profiles here are hearsay statements. 

¶13 We also note that the profiles were not introduced 

into evidence as exhibits at Gomez’s trial; the analyst simply 

testified about them. In Banville, the Massachusetts Supreme 
7 

Judicial Court held that the Confrontation Clause is not 

offended when an expert relies on testimonial hearsay to form an 

opinion so long as the expert does not testify to the details of 

the hearsay and the hearsay itself is not admitted. See 

Banville, 931 N.E.2d at 466-67. The expert in this case did not 

testify in detail about the DNA profiles and, as in Banville, 

the profiles were not admitted into evidence as exhibits. 

Nonetheless, without deciding the issue, we assume that the 

analyst’s testimony here was functionally equivalent to the 

introduction of the profiles into evidence. 

¶14 In considering Gomez’s argument that the analyst’s 

testimony about the profiles violated the Sixth Amendment, we 

start from the premise that the Confrontation Clause does not 

require that every person in the chain of custody be available 

for cross-examination. Melendez-Diaz expressly rejected the 

notion that “anyone whose testimony may be relevant in 

establishing the chain of custody, authenticity of the sample, 

or accuracy of the testing device, must appear in person as part 

of the prosecution’s case.” 129 S. Ct. at 2532 n.1. Rather, 

the Court emphasized that “[i]t is up to the prosecution to 

decide what steps in the chain of custody are so crucial as to 

require evidence; but what testimony is introduced must (if the 

defendant objects) be introduced live.” Id. The Sixth 
8 

Amendment requires only that those who do testify about the 

chain of custody be available for cross-examination. Id.

¶15 Gomez does not contend in this Court that the chain of 

custody of the DNA samples was insufficiently established. 

Police officers testified that the evidence was collected and 

sent to the laboratory, and the analyst testified that the 

evidence was received, processed, tested, and returned. The 

analyst testified from her own knowledge not only about the 

laboratory’s general procedures, but also about the records kept 

by the laboratory in this case. The chain of custody testimony 

did not violate the Confrontation Clause simply because every 

technician who handled and processed the samples did not 

testify. See Melendez-Diaz, 129 S. Ct. at 2532 n.1. 

¶16 The remaining question, then, is whether Gomez’s 

inability to cross-examine the technicians deprived him of his 

confrontation rights with respect to the analyst’s testimony 

about the profiles. If the DNA profiles are hearsay statements, 

they are in effect statements of the processing machine about 

the data contained in the samples. The profiles contain neither 

the opinion nor the statement of the technicians. The machine, 

of course, cannot be cross-examined. The issue thus is whether 

the Confrontation Clause was satisfied because the analyst, 

rather than the technicians, was available for crossexamination. 
9 

¶17 In virtually identical circumstances, several courts 

have held that the testimony of a witness with knowledge of how 

the profiles were prepared satisfies the Sixth Amendment. The 

Indiana Supreme Court’s decision in Pendergrass is particularly 

instructive. In that case a laboratory supervisor testified 

regarding the processing of DNA evidence. 913 N.E.2d at 704. 

The supervisor had checked the work of the processors and 

testified about the laboratory’s operating procedures. Id. at 

707-08. Certificates containing data about the DNA profiles 

generated at the laboratory were introduced into evidence during 

the supervisor’s testimony. Id. at 704. A separate witness 

then compared the profiles and drew conclusions as to whether 

the defendant was the father of a rape victim’s aborted fetus. 

Id. at 705. 

¶18 The defendant in Pendergrass contended that the 

certificates should not have been admitted into evidence without 

the testimony of the employees who processed the samples. The 

Indiana Supreme Court rejected that argument, pointing out that 

the primary purpose of cross-examination is to test the 

reliability of a statement. See id. at 708. In Pendergrass, as 

here, the supervisor “would be a competent witness, perhaps the 

ideal witness, against whom to lodge such challenges,” because 

she “had personal knowledge of the laboratory’s work on the 

specimens at issue as the person who performed the technical 
10 

review.” Id. The Indiana court distinguished Melendez-Diaz, 

noting that the defendant in Melendez-Diaz had no opportunity to 

cross-examine anyone “involved in the substantive analysis.” 

Id. 

¶19 United States v. Boyd, 686 F. Supp. 2d 382 (S.D.N.Y. 

2010), reached the same conclusion on facts indistinguishable 

from those before us. In Boyd, as here, a laboratory supervisor 

testified to the laboratory processes and results. Id. at 385. 

The supervisor had compared the DNA profiles generated by the 

laboratory but had not witnessed some of the preceding steps, 

which were performed by technicians. Id. at 384-85. The court 

found no Confrontation Clause violation, noting that the 

testimony showed that the laboratory had established procedures, 

there was “little to no discretion” in executing the other steps 

of the testing process, and the technicians would have been 

“less able to respond to questions about the intervening 

procedures than the more expert witness who was actually called 

to the stand.” Id. at 385. The court observed that 

[o]nly the final stage of the DNA testing involved the 

type of analytical judgment for which a certificate 

would be an inadequate substitute for in-court 

testimony under the Sixth Amendment. But this was 

precisely where the Government provided live testimony 

in the form of the expert who performed this step. 

Id.
11 

¶20 Consistent with Pendergrass and Boyd, other 

jurisdictions have held that DNA profiles may be admitted at 

trial when the laboratory technicians who handled the samples 

and obtained the machine-generated data do not testify, as long 

as someone familiar with the profiles and laboratory procedures 

is subject to cross-examination. See, e.g., Vann v. State, 229 

P.3d 197 (Alaska Ct. App. 2010); Aguilar v. Commonwealth, 699 

S.E.2d 215 (Va. 2010); see also State v. Dilboy, 999 A.2d 1092 

(N.H. 2010) (involving an expert testifying about a toxicology 

report he had not prepared personally); State v. Bullcoming, 226 

P.3d 1, 9 (N.M. 2010), cert. granted, 131 S. Ct. 62 (U.S. Sep. 

28, 2010) (finding Confrontation Clause satisfied when gas 

chromatograph evidence was admitted without testimony of analyst 

who prepared report, because another qualified analyst was 

subject to cross-examination at trial; characterizing original 

analyst as a “mere scrivener;” concluding that “the live, incourt testimony of a separate qualified analyst is sufficient to 

fulfill a defendant's right to confrontation”). Here, as in 

these cases, the processing technicians performed no analysis, 

and the testifying analyst had extensive knowledge of the 

laboratory’s procedures, had reviewed the technicians’ work, and 

was familiar with the machine-generated data. 

¶21 We find the reasoning in these cases compelling. The 

technicians at most could have testified about the mechanical 
12 

steps they took to process the DNA samples. The analyst was 

able to review that work, testify from her own knowledge as to 

the procedures used, and answer questions during crossexamination about the accuracy of the end results. The 

analyst’s testimony therefore did not offend the Confrontation 

Clause. 

B. 

¶22 Regarding the analyst’s expert opinion, we repeatedly 

have held that the Confrontation Clause is not violated when an 

expert bases testimony on data provided by others who are not 

subject to cross-examination. We have held that a medical 

examiner may offer an expert opinion based on review of reports 

and test results prepared by others, as long as the testifying 

expert does not simply “act as a conduit for another nontestifying expert’s opinion.” State v. Snelling, 225 Ariz. 182, 

187 ¶ 19, 236 P.3d 409, 414 (2010) (internal quotation marks 

omitted) (quoting State v. Smith, 215 Ariz. 221, 228 ¶ 23, 159 

P.3d 531, 538 (2007)). In Snelling, the testifying medical 

examiner reviewed photographs of the victim and an autopsy 

report prepared by another pathologist and offered opinions as 

to cause of death based on the test results in that report. Id.

at ¶ 20. We confirmed that the defendant’s confrontation right 

extended only to the testifying witness, not to those whose 

findings formed the basis for the witness’s opinion. Id.; see 
13 

also Smith, 215 Ariz. at 228-29 ¶¶ 21-26, 159 P.3d at 538-39 

(finding no Confrontation Clause violation when an expert, in 

forming independent conclusions, reasonably relies on 

information obtained from others not testifying at trial); cf.

Ariz. R. Evid. 703 (allowing expert testimony to be based on 

facts or data otherwise not admissible, “[i]f of a type 

reasonably relied upon by experts in the particular field in 

forming opinions or inferences upon the subject”). 

¶23 As in Snelling, the analyst here did not act as a 

“conduit” for the opinions of others. See Snelling, 225 Ariz. 

at 187 ¶¶ 19, 20, 236 P.3d at 414. Rather, she formed her own 

opinions, based on a type of data normally relied upon by 

experts in her field. See id. at ¶ 20; Smith, 215 Ariz. at 228 

¶ 24, 159 P.3d at 538. We found no Confrontation Clause 

violation in Snelling, even though the testifying medical 

examiner “referred to the [autopsy] report’s findings,” 225 

Ariz. at 187 ¶ 20, 236 P.3d at 414, because the examiner reached 

her own conclusions and was subject to cross-examination as to 

those conclusions, id.; see also United States v. Turner, 591 

F.3d 928, 930 (7th Cir. 2010) (supervisor allowed to testify to 

independent conclusions as an expert witness on the basis of a 

report generated by forensic analyst); United States v. 

Richardson, 537 F.3d 951, 960 (8th Cir. 2008) (analyst allowed 

to testify to independent conclusions as an expert witness on 
14 

basis of her review of results of testing conducted by another 

analyst); Vann, 229 P.3d at 210 (same). 

¶24 The testifying expert in this case was subject to 

cross-examination about her independent conclusion that several 

of the DNA profiles came from the same person. The analyst’s 

reliance on data obtained from non-testifying witnesses in 

arriving at her opinion did not violate the Confrontation 

Clause. 

IV. 

¶25 Gomez requested a jury instruction that “[t]he work of 

non-testifying witnesses is admitted only to allow the 

consideration of the reasons for the expert’s opinion.” He 

argued that the instruction was compelled by Arizona Rule of 

Evidence 105, which provides that “[w]hen evidence which is 

admissible . . . for one purpose but not admissible . . . for 

another purpose is admitted, the court, upon request, shall 

restrict the evidence to its proper scope and instruct the jury 

accordingly.” The trial court rejected the proposed instruction 

as a comment on the evidence. The court of appeals upheld the 

denial of the instruction on different grounds, finding the 

instruction legally flawed. Gomez, 1 CA-CR 08-0318 at ¶ 27. 

¶26 The court of appeals correctly noted that a trial 

court generally does not have to separate the good from the bad 

in a proposed instruction. See State v. Mitchell, 204 Ariz. 
15 

216, 220 ¶ 22, 62 P.3d 616, 620 (App. 2003). Rule 105, however, 

mandates a limiting instruction on request. The submission of 

an inadequate instruction does not waive the defendant’s right 

to a limiting instruction in a case covered by Rule 105. 

Readenour v. Marion Power Shovel, 149 Ariz. 442, 451, 719 P.2d 

1058, 1067 (1986) (holding that rejection of an inadequate 

instruction “should not be used as a reason for giving no 

instruction at all” (internal quotation mark omitted) (quoting 1 

J. WEINSTEIN & M. BERGER, WEINSTEIN’S EVIDENCE ¶ 105[05] at 105-

37 (1985))). 

¶27 We nonetheless find no reversible error. Rule 105 

applies only when the evidence “is admissible . . . for one 

purpose but not admissible . . . for another purpose.” Because 

the DNA profiles were not themselves admitted into evidence, the 

instruction Gomez requested necessarily related to the analyst’s 

testimony about the profiles. In contrast to Snelling, where 

testimony about the underlying data was offered only to support 

an expert opinion, the analyst’s testimony here about the DNA 

profiles was not so limited. The analyst testified as an expert 

on DNA, but also established the chain of custody, testified how 

the evidence submitted by the police to the laboratory was 

processed, and explained how DNA profiles were derived from that 

evidence. Her testimony thus was offered to demonstrate that 

the profiles were in fact generated from DNA obtained at the 
16 

crime scene and from Gomez. Because the analyst’s testimony 

about the profiles was not submitted simply to support her 

expert opinion, a limiting instruction was not required. 

IV. 

¶28 For the reasons above, we affirm Gomez’s convictions 

and sentences, but vacate ¶¶ 21-27 of the memorandum decision of 

the court of appeals. 

 _____________________________________

 Andrew D. Hurwitz, Vice Chief Justice

CONCURRING: 

_____________________________________

Rebecca White Berch, Chief Justice

_____________________________________

W. Scott Bales, Justice

_____________________________________

A. John Pelander, Justice

_____________________________________

J. William Brammer, Jr., Judge∗

                                                           

∗

 Pursuant to Article 6, Section 3 of the Arizona 

Constitution, the Honorable J. William Brammer, Jr., Judge of 

the Arizona Court of Appeals, Division Two, was designated to 

sit in this matter.