Are police officers allowed to lie during a casual conversation or while questioning a suspect to obtain information?

Legally, yes, police officers are able to use deceptive tactics, or lie, in order to receive information.

Most officers (and detectives) would agree that lying should be avoided when possible, but there are times when lying is necessary to uncover the truth during an investigation.

The fact that the officer lied can be used as a defense in court as possible coercion (which is not always a successful defense), but the officer cannot be held legally accountable for lying.