## Facts

- Michael Cavallo and David R. Murro were indicted for offenses arising from a June 16, 1977 encounter with S.T., a married woman who was two months pregnant.
- After midnight, S.T. met Murro at a bar near her home; he invited her to smoke marijuana with him and Cavallo in Cavallo’s car, and she left the bar with them.
- The parties gave sharply conflicting accounts of what followed: S.T. claimed she was abducted and raped; defendants claimed she voluntarily accompanied them and the sexual activity was consensual.
- There were no witnesses other than S.T. and the defendants; the trial centered on credibility.
- At trial, Cavallo sought to introduce testimony from a psychiatrist who would opine that Cavallo was non-violent and non-aggressive, knew rape was wrongful, and did not exhibit traits the psychiatrist associated with “rapists.”
- The trial court excluded the proffered expert character testimony; defendants were convicted, and the convictions were affirmed on appeal.

## Issues

1. Whether a rape defendant may offer psychiatric expert character testimony that he lacks “psychological traits of a rapist” under the character-evidence rule.
2. Whether such testimony satisfies the expert-opinion admissibility and reliability requirements, including general acceptance in the relevant scientific community.

## Decision

- The Supreme Court of New Jersey affirmed the exclusion of the psychiatric character evidence and left the convictions undisturbed.
- The court treated the proffer as relevant character evidence in the abstract, but held it inadmissible because it failed the reliability requirements for expert testimony.
- The defense did not establish that (1) rapists have a distinct psychological profile and (2) psychiatrists can reliably diagnose the absence of such traits in an individual through clinical examination.
- Applying the Frye general-acceptance test to scientific expert evidence, the court found no adequate showing of acceptance in the relevant scientific community through supporting expert testimony, literature, or persuasive judicial authority.
- The court also noted the risk that this type of expert opinion, presented as scientific, could mislead the jury and effectively substitute an expert’s credibility judgment for the jury’s role in a case turning on disputed accounts.

## Legal Principles

- A criminal defendant may offer character evidence to suggest improbability of committing the charged offense, but expert character evidence is admissible only if it meets the standards for expert testimony.
- Expert opinion testimony must rest on a sufficiently reliable scientific or specialized basis and fall within accepted professional knowledge and methodology.
- For novel or scientific propositions, reliability is assessed by whether the underlying principle or technique has achieved general acceptance in the relevant scientific community (Frye).
- Psychiatric testimony asserting a defendant’s lack of “rapist traits” is properly excluded when the proponent fails to show general acceptance that rapists can be reliably distinguished from non-rapists through clinical psychiatric profiling.
- Courts may exclude expert evidence that, despite marginal relevance, carries a substantial risk of misleading the jury or displacing the jury’s credibility determinations.

## Conclusion

The court held that psychiatric “rapist profile” character testimony was inadmissible because the defense failed to demonstrate that the asserted profiling theory and diagnostic method were scientifically reliable and generally accepted, and the exclusion was affirmed along with the convictions.


State v. Cavallo, 88 N.J. 508, 443 A.2d 1020 (1982)