Nice guy, tough guy

Nice guy, tough guy was a police tactic for interrogating suspects. One police officer would speak harshly and threaten the suspect with harsh punishments for unconfessed crimes, while another would speak gently, acting as the suspect's friend and offering rewards in the form of reduced punishment in exchange for information about the criminal network. Thomas Bushell and Samuel Stanley used this tactic in scores of interrogations, with Bushell playing "tough" and Stanley playing "nice."

Literary comment
Equivalent to the OTL practice of "good cop, bad cop."