Research has shown that a comparable truth baseline (CTB) approach elicits more cues to deception and results in higher accuracy rates than a small talk baseline. Past research focused on laypeople’s accuracy rates. We examined whether the CTB also has a positive effect on law enforcement personnel accuracy. In this study, 95 police officers judged 10 interviews, whereby half of the senders told the truth, and the other half lied about a mock undercover mission. Half of the interviews included only questioning about the event under investigation, whereas the other half also included questioning aimed at creating a CTB. Total and truth accuracy did not differ, but Observers who watched interviews with a CTB obtained higher lie detection accuracy rates than those who watched interviews without the baseline questioning. Signal detection analyses showed that this effect could be attributed to a decreased response bias in the CTB condition.