Problems with the confrontation clause in surrogate expert testimony have increasingly become a major issue in modern criminal trials. As courts rely more heavily on forensic science, medical examinations, and digital evidence, prosecutors sometimes attempt to introduce testimonial conclusions through a substitute witness. This practice raises serious constitutional concerns because the Sixth Amendment guarantees a defendant the right to confront the actual witness who made those statements. The U.S. Supreme Court, and numerous federal appellate courts, have made clear that surrogate testimony cannot be used to bypass confrontation rights. Its most recent decision, Smith v. Arizona (2024), removes any remaining ambiguity.
Below is the complete landscape of controlling Supreme Court precedent and the corresponding federal circuit rulings interpreting and applying those decisions.
I. Supreme Court Limits on Surrogate Expert Testimony and the Confrontation Clause
A. Melendez-Diaz v. Massachusetts, 557 U.S. 305 (2009)
The Court held that forensic certificates, such as drug-analysis reports, are testimonial because they are created for the purpose of prosecution. Analysts who author them must testify, and their absence cannot be cured by calling another witness to read or summarize their findings.
B. Bullcoming v. New Mexico, 564 U.S. 647 (2011)
The Court prohibited the government from calling a “surrogate analyst” to testify about laboratory results produced by a different, non-testifying analyst. The surrogate had no role in performing or observing the test, nor did he certify the report.
Key rule:
The Confrontation Clause forbids admitting testimonial forensic evidence through a witness who did not perform, observe, or meaningfully review the testing.
C. Williams v. Illinois, 567 U.S. 50 (2012)
A fractured plurality permitted limited expert testimony referencing a private lab’s DNA report, but the decision produced no binding majority rule. Four Justices concluded the testimony violated the Confrontation Clause; four found it admissible; Justice Thomas concurred only on a narrow ground.
D. Ohio v. Clark, 576 U.S. 237 (2015)
The Court reaffirmed the primary purpose test: a statement is testimonial if its primary purpose is to establish facts for use in prosecution. This includes scientific or medical observations made for law-enforcement purposes.
E. Smith v. Arizona, 602 U.S. 779 (2024)
The most recent and controlling rule: testimonial statements cannot be funneled to the jury through a surrogate expert.
The Supreme Court held:
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When an expert conveys the substance of a non-testifying analyst’s conclusions,
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And those conclusions would be inadmissible if offered directly,
the statements are being introduced for their truth and the Confrontation Clause applies.
It does not matter whether the underlying report is formally admitted.
It does not matter if the expert claims to offer an “independent” opinion.
If the expert relies on, adopts, or repeats testimonial statements from another analyst, the original analyst must testify.
Smith resolves the uncertainty left by Williams and strongly reinforces Melendez-Diaz and Bullcoming.
II. Federal Circuit Decisions Applying Surrogate Expert Testimony Principles
Federal appellate courts have applied these principles in a wide range of contexts, including digital forensics, drug analysis, autopsies, and toxicology. Their decisions fall into two categories:
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Cases finding Confrontation Clause violations (when a surrogate merely repeats another analyst’s conclusions).
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Cases finding no violation (when the testifying expert genuinely performed, observed, supervised, or independently reviewed the underlying analysis).
A. Cases Highlighting Confrontation Problems with Surrogate Testimony
1. United States v. Soto, 720 F.3d 51 (1st Cir. 2013)
Agent Pickett testified that he conducted an independent forensic examination of a hard drive but also stated that a non-testifying analyst’s findings were “exactly” correct. The First Circuit cautioned that repeating the absent analyst’s conclusions risks violating the Confrontation Clause—even if the surrogate also conducted a partial review.
Takeaway: Repeating or affirming testimonial statements made by a non-testifying analyst crosses into prohibited surrogate testimony.
2. Garlick v. Lee, 15 F.4th 259 (2d Cir. 2021)
The Second Circuit affirmed habeas relief after New York courts admitted an autopsy report through a surrogate medical examiner. The original examiner did not testify. The report was deemed testimonial because it was created during a homicide investigation and intended for prosecution.
Takeaway: Autopsy reports prepared for law enforcement can be testimonial, and defendants have the right to confront the examiner who authored them.
3. Grim v. Fisher, 816 F.3d 296 (5th Cir. 2016)
Although the Fifth Circuit ultimately denied habeas relief under AEDPA, it acknowledged that Bullcoming prohibits introducing a forensic report through a witness with no involvement. Grim’s conviction stood only because Bullcoming did not clearly define the minimum required involvement under AEDPA’s demanding standard.
Takeaway: While the constitutional violation was likely, AEDPA’s “clearly established law” standard prevented relief.
4. Jenkins v. Hall, 910 F.3d 828 (5th Cir. 2018)
A supervisor who reviewed and co-signed a report—yet did not perform or observe the testing—testified in place of the absent analyst. Relief was denied under AEDPA for similar reasons as Grim: the Supreme Court had not clearly established the exact involvement required when a supervisor signs off on a report.
Takeaway: Notably, Jenkins and Grim do not approve surrogate testimony as constitutional—they simply declined relief under AEDPA’s limited scope.
B. Cases Upholding Testimony When the Testifying Expert Had Direct Involvement
1. United States v. Walker, 990 F.3d 316 (3d Cir. 2021)
The Third Circuit found no violation where the testifying agent personally reviewed cell-site and phone data and formed his own conclusions. The agent did not merely adopt another analyst’s conclusions.
Takeaway: No confrontation problem exists when the testifying expert has personal involvement and does not serve as a conduit for testimonial hearsay.
2. United States v. Mouzone, 687 F.3d 207 (4th Cir. 2012)
Two chemists analyzed the same drug samples at different times. Although the admitted report contained data from both analysts, the testifying chemist independently tested the drugs, explained her own methods, and did not rely on the absent analyst’s conclusions.
Takeaway: Independent re-testing and independent conclusions avoid surrogate testimony problems.
3. United States v. Taylor, 2024 U.S. App. LEXIS 1854 (6th Cir. Jan. 25, 2024)
A supervising toxicologist testified about a toxicology report he signed and certified after independently reviewing all underlying data. Because he authored the testimonial statements himself, the Sixth Circuit held there was no Confrontation Clause violation.
Takeaway: If the testifying expert is the person who made the testimonial statement, confrontation is satisfied—even if subordinate analysts performed the raw testing.
III. Unified Rule Governing Surrogate Expert Testimony
If you or someone you know is facing this issue, you need to reach out to an attorney who understands it.
Surrogate expert testimony violates the Confrontation Clause when:
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testimonial statements are introduced through a substitute witness,
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the analyst who made the statement does not testify, and
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the testifying expert conveys or adopts those statements for their truth.
Across Supreme Court and federal appellate decisions, the constitutional principle is clear:
A defendant has the right to confront the analyst who actually made the testimonial statement, not a surrogate.