Hmmmm this is a tough one, but I'd have to say that, as long as good ethics are in play, lying in order to get the prisoner to trip up on their own lies is acceptable in my book. Lying to the point of bullying is not OK. Lying in any way that will forever harm the prisoner psychologically is also not acceptable. However, small lies in order to poke the holes in another's story are just a tool at a police officers disposal.

Age 26, Software Test Technician.