The effects of warning witnesses about lying (i.e., turncoat warning) and rapport building on perceptions of police interviewers were examined across two experiments. In experiment 1, participants (N = 59) were asked to assume the role of a witness when reading four interview transcript excerpts and rate the police interviewer on an eight-item attitudinal scale. Interviewers who warned witnesses about lying were viewed less favorably than when no warning was administered. Interviewers who used rapport-building techniques were viewed more favorably than those who did not attempt to build rapport. There was also a moderating interaction, whereby the use of rapport-building techniques offset the lower attitudinal ratings associated with the administration of the warning. In experiment 2, participants (N = 46) were asked to assume the role of a third party observer when reading four interview transcript excerpts and rate the police interviewer on a ten-item attitudinal scale. Results of experiment 2 replicated the findings from experiment 1. The potential implications of starting an interview by warning a witness about lying are discussed.