ON PETITION FOR WRIT OF CERTIORARI TO THE SUPREME COURT OF DELAWARE.
In this case, the Delaware Supreme Court reversed respondent William Fensterer's conviction on the grounds that the admission of the opinion testimony of the prosecution's expert witness, who was unable to recall the basis for his opinion, denied respondent his Sixth Amendment right to confront the witnesses against him. 493 A. 2d 959 (1985). We conclude that the Delaware Supreme Court misconstrued the Confrontation Clause as interpreted by the decisions of this Court.
Respondent was convicted of murdering his fiancee, Stephanie Ann Swift. The State's case was based on circumstantial evidence, and proceeded on the theory that respondent had strangled Swift with a cat leash. To establish that the cat leash was the murder weapon, the State sought to prove that two hairs found on the leash were similar to Swift's hair, and that one of those hairs had been forcibly removed. To prove these theories, the State relied on the testimony of Special Agent Allen Robillard of the Federal Bureau of Investigation.
At trial, Robillard testified that one of the hairs had been forcibly removed. He explained that, in his opinion, there are three methods of determining that a hair has forcibly
been removed: (1) if the follicular tag is present on the hair, (2) if the root is elongated and misshaped, or (3) if a sheath of skin surrounds the root. However, Robillard went on to say that "'I have reviewed my notes, and I have no specific knowledge as to the particular way that I determined the hair was forcibly removed other than the fact that one of those hairs was forcibly removed.'" Id., at 963. On cross-examination, Agent Robillard was again unable to recall which method he had employed to determine that the hair had forcibly been removed. He also explained that what he meant by "forcibly removed" was no more than that the hair could have been removed by as little force as is entailed in "'brushing your hand through your head or brushing your hair.'" Pet. for Cert. 7. The trial court overruled respondent's objection that the admission of Robillard's testimony precluded adequate cross-examination unless he could testify as to which of the three theories he relied upon, explaining that in its view this objection went to the weight of the evidence rather than its admissibility.
The defense offered its own expert in hair analysis, Dr. Peter DeForest, who agreed with Agent Robillard that the hairs were similar to Swift's. Doctor DeForest testified that he had observed that one of the hairs had a follicular tag. He also testified that he had spoken by telephone with Robillard, who advised him that his conclusion of forcible removal was based on the presence of the follicular tag. App. to Pet. for Cert. D-2. Doctor DeForest then proceeded to challenge the premise of Robillard's theory -- that the presence of a follicular tag indicates forcible removal. According to Dr. DeForest, no adequate scientific study supported that premise, and a follicular tag could be attached to hairs that naturally fall out.
On appeal, the Delaware Supreme Court reversed respondent's conviction on the authority of the Confrontation Clause. Noting that "[the] primary interest secured by the Clause is the right of cross-examination," 493 A. 2d, at 963,
the court reasoned that "[effective] cross-examination and discrediting of Agent Robillard's opinion at a minimum required that he commit himself to the basis of his opinion." Id., at 964 (footnote omitted). Absent such an acknowledgment of the basis of his opinion, the court believed that "defense counsel's cross-examination of the Agent was nothing more than an exercise in futility." Ibid. Since the court could not rule out the possibility that Robillard could have been "completely discredited" had he committed himself as to the theory on which his conclusion was based, it held that respondent "was denied his right to effectively cross-examine a key state witness." Ibid. Accordingly, the court reversed without reaching respondent's additional claim that Robillard's testimony was inadmissible under the pertinent Delaware Rules of Evidence. We now reverse the ...