'''Basic Trope''': Two police officers (or similar) interrogate a suspect by taking on different personas; the 'good' cop who acts reasonable, and the 'bad' cop who acts aggressive.
* '''Straight''': Bob and Carl interrogate Eddie, their murder suspect. Bob acts calm and reasonable, suggesting that it's better for Eddie that he confess; Carl acts aggressive, hinting that he's willing to beat it out of Eddie if necessary.
* '''Exaggerated''':
** Bob is incredibly gentle, almost pleading with Eddie; Carl practically has to be dragged off Eddie.
** It isn't an act. Carl really is that aggressive, and Bob is desperately trying to restrain his behavior.
** Bad Cop/Worse Cop: Carl is an aggressive bastard, but Bob is such a complete psychopath (or pretending to be one) that Eddie pleads to Carl that he will provide any information the investigation warrants as long as Bob isn't in the room trying to cut his toes off with a knife.
** The whole police station is divided in "nice cops" and "angry cops" divisions.
* '''Downplayed''':
** Bob is polite towards Eddie, while Carl treats him with businesslike coldness.
** Bob is amiable (to a point) but Carl is your standard cop-show sarcasm-filled jackass that openly disbelieves any and all of Eddie's attempts to prove his innocence.
* '''Justified''':
** One cop acting aggressive and intimidating the suspect makes it possible that the suspect will gravitate towards the more reasonable seeming cop in order to secure a confession.
** The routine is an extension of [[RedOniBlueOni their personalities]]; Bob is [[ByTheBookCop a more cool-headed, rational and calm police officer]] in contrast to the [[CowboyCop hot-headed, aggressive and rule-stretching]] Carl.
* '''Inverted''':
** Bob and Carl are two criminals who interrogate Eddie, a cop, in this fashion in order to discover how much their criminal enterprise has been compromised.
** When being interrogated, Eddie acts incredible aggressive and hostile towards Carl, but mild and meek with Bob.
* '''Subverted''':
** Carl acts incredibly aggressive towards Eddie, making it seem as if Bob will be the good cop. Bob, however, is the Worse Cop, and acts even more aggressive and confrontational than Carl did.
** Both Bob and Carl are reasonable and cool-headed.
* '''Double Subverted''':
** Carl intimates that Bob will be even worse than he was, but Bob is still playing the good cop.
** Bob emphasizes the good parts of cooperating in his talks, while Carl insinuates what may befall him if he refuses to cooperate. Both do so in a calm manner, making Carl able to unnerve Eddie by discussing almost nonchalantly things like known perps already in prison that wouldn't hesitate to gut Eddie like a fish.
* '''Parodied''':
** Bob and Carl have trouble keeping which 'cop' they're supposed to be straight, and keep switching.
** Bob is ''too'' nice, and / or Carl is ''too'' aggressive.
** Bob and Carl push the concept a little too far, and begin indulging in other types of 'cops', with the result that the suspect is hit with such combos as 'Absent Minded Cop / Overly Fastidious Cop'. The suspect is a bit bewildered to say the least.
** Only Carl is around, and tries to pull off both personas. the inmate just sits there [[DullSurprise with a slightly confused expression.]]
** Only Carl is around, and he ''succeeds'' in pulling off both personas and getting Eddie to confess.
** Good Cop/[[http://xkcd.com/1018/ Dadaist Cop]]
** The lines between Bob, Carl and the suspect begin to blur until the suspect is taking on 'cop' roles and both Bob and Carl are playing the suspect.
** Bob and Carl get too caught up in the clashing personalities fundamental in this trope and begin to bicker with each other to the extent that they start to forget about the suspect entirely.
** Bob and Carl try playing a "cop" that is diametrically opposed to their normal personality and can't quite manage to overcome it, leading to such situations as "Bad Cop" Bob sheepishly apologising after every "bad" thing he does (most of which [[PokeThePoodle aren't as bad as he thinks]]), while "Good Cop" Carl can barely keep the lid on his simmering rage enough to offer the suspect a cup of water without it seeming like a death threat.
** Bad Cop/Apathetic Cop
* '''Zig Zagged''': Bob and Carl switch over who is the good cop and who is the bad cop.
* '''Averted''': Bob and Carl use interrogation techniques other than this one.
* '''Enforced''': DaChief orders Bob and Carl to use the technique on the suspect they're about to question.
* '''Lampshaded''':
** If the perp suspects that this is happening or about to happen: "Oh come on -- are you guys seriously doing the whole 'good cop / bad cop' thing with me?"
** If the bad cop is surprised the "good cop" is actually the "worse cop": "I thought ''I'' was supposed to be the bad cop?"
* '''Invoked''':
** Before the interrogation, Bob and Carl agree to try 'good cop / bad cop' on the perp and agree on their roles beforehand.
** DaChief makes [[ByTheBookCop Bob]] and [[CowboyCop Carl]] partners, because he knows their personalties will let them do this.
* '''Exploited''': Basically every time it is in use.
* '''Defied''':
** The suspect is a career criminal who has been arrested multiple times and is prepared for the standard police interrogation tactics, meaning that Bob and Carl will have to search their playbook for a tactic more likely to work.
** The suspect immediately asks for a lawyer and refuses to answer any of the cops' questions just as they're about to try this.
** DaChief brings down the banhammer on this technique; it's either full-blown polite and professional behavior at all times during an interrogation or he will start making heads roll.
* '''Discussed''': "Everyone's heard of it, but you'd be surprised how often 'good cop / bad cop' works -- you really would."
* '''Conversed''': "Are there any other interrogation tactics than 'good cop / bad cop'?
* '''Deconstructed''': Because of the popularity of television shows using this trope, criminals who are arrested are prepared and almost expect the 'good cop / bad cop' routine, making Bob and Carl's life more difficult.
* '''Reconstructed''': Just because the perps expect it doesn't necessarily mean it still can't be effective from time to time, however; particularly with suspects who, while they might have seen a lot of cop shows, are not prepared for the actuality of being in a genuine police interrogation.
----
-> '''Bob''': "Why not go back to GoodCopBadCop? It'll be easier for you and all of us if you do."\\
'''Carl''': "And if you don't, punk, I'll ''bounce you off the walls'', you dig?"
----
%% Optional items, added after Conversed, at your discretion:
%%
%%* '''Implied''': ???
%%* '''Plotted A Good Waste''': ???
%%* '''Played For Laughs''': ???
%%* '''Played For Drama''': ???