Geez, which one?
Which murder, I mean. There’s only one Gibbs. Thank Athena.
Miller’s Crossing. (Of course, it’s a gangster-crime movie, no “good guys” as such.)
Not to mention Hamlet, where the “good guy” Prince Hamlet kills several “bad guys”, including Polonius and Claudius.
Did he?
Along the same lines, Michael Weston of Burn Notice does this a lot in the first few seasons (not pulling the trigger, but ensuring someone will). And closer to the OP, at the end of a recent season (3?), he actually does kill a bad guy in an abrupt and surprising ending (although he had at least two good reasons).
In one episode of The Closer, Chief Brenda learns the suspect has committed murder only after he was granted immunity to testify about a different, related murder – an attempt on his own life as revenge for the first murder (which was of an old man at a candy store nobody in his 'hood ever touches, by general agreement, and of a child witness), which he blamed on a second homeboy, who then tried to murder him and got his twin brother and friends by mistake.
Brenda, having finally got the goods to nail Homeboy 2, is entirely frustrated she has to release HB1, who is equally a murder and started the whole thing.
But she does explain the situation to HB2 and then advises him he can make as many phone calls as she likes.
She then drives HB1 home. And drops him off there. In the hood where every tough dude is suddenly glaring at him. And leaves. Chief Brenda pulls no trigger. But, knowingly leaving any person in an extemely dangerous situation really is the sort of thing for which a cop should get kicked off the force at the very least. Doing it with malice aforethought like that is probably a count of homicide.
I just watched Sarah shoot a guy in the coldest of blood. (I think I’m in Season 2 currently)
There’s an early Spenser novel where Spenser feels like he’s out of options and sets up some bad guys with an ambush, where he takes them down from, IIRC, a sniper position.
How about Kevin Costner pushing Frank Nitti off the roof in The Untouchables?
Well, CSI’s current lead character, Dr. Ray Langston, committed murder.
OTOH, his victim was a serial killer who’d stabbed and almost killed him months previous, and had just tortured Langston’s ex-wife with, among other things, dozens of fishhooks, so despite the fact that Langston had the guy cuffed, then let him go solely to beat and eventually kill him, YMMV on how “cold blooded” it was.
Would have been dandy if you put a “book, not the tv series (yet)” in there somewhere.
It’s Mortal Stakes, though he’s using a shotgun; I don’t think that counts as being a sniper. He goes the shotgun route because he knows he’ll be the first suspect, as Quirk & Belson have just warned him that the two criminals in question are gunning for him. It’s made clear that Quirk believes Spenser killed them (he already knows what Spenser is capable of), but since the murders don’t take place in Boston proper, Quirk doesn’t feel obliged to investigate, though he does warn Spenser never to do it in Boston.
That’s not Spenser’s last murder, though he doesn’t do it in Boston again. In A Catskill Eagle, he’s complicit in at least three cold-blooded killings, one of an unarmed man.
In Miami Vice, Don Johnson’s Sonny Crockett married a woman played by Sheena Easton, then a crimelord had her shot at one of her concerts. Sonny tracked the guy to some island without an extradition treaty, and killed him as he lounged by his pool. A second after the fool said Crockett would never do such a thing.
In CSI: Miami, Horatio Caine married the sister of one of his techs, and she was killed. The two of them followed the killer to Brazil, where Horatio threatened the guy until the killer pulled a knife. Caine took it away from the guy and stabbed him to death with it.
Of Mice and Men, I guess not exactly a “Bad Guy” but still…
Thanks, Skald. Your memory of it was much clearer than mine. 
We just had a thread about it! Not to mention that I’ve been rereading them.
In one of the Stephen Hunter books, Bob Lee Swagger figures out that the highly-placed Russian mole bad guy is now the head of the CIA that had helped him kill a Russian sniper from the old days who had tried to kill his family, and kills him and his henchmen with a claymore in the last scene.
Indeed I have and that epiphany was the realization that Lucas is a no-talent hack who has built his career on the work of others.
And again I’m surprised when I realize there’s been no mention of Jack Bauer in this thread.
He doesn’t commit cold blooded murder just at the end, he does it several times during every twenty-four hours.