During a BAI, a protocol of questions is asked, and suspects' verbal responses and accompanying nonverbal behaviors and attitudinal characteristics are assessed to determine their likelihood of involvement in the crime. The suspects in the study had all been interviewed on the premises of J. Reid and Associates. Their truthfulness or deception had been established by means of confessions or information developed independently. Each of the four evaluators independently scored suspects' behaviors and attitudes and assessed the suspect's truthfulness. Results revealed that, excluding inconclusive decisions, evaluators' average accuracy was 91 percent on truthful suspects and 80 percent on deceptive suspects. The suspects' status did not affect the confidence of the evaluators' decisions, but the confidence was greater when correct as opposed to incorrect calls were made. Findings indicated that the BAI appears to be useful for investigative purposes to differentiate between suspects who are concealing involvement in a criminal offense from those who are not. Tables and 29 references (Author abstract modified)