How does Matt Damon’s account of the climactic events hold up under scrutiny? Leo’s gun is used to kill both Officer Brown and Detective Barrigan at the end. Any police investigation would have questions about how this happened, and the last man standing would have to answer them.
shareGood question but I think it would be easy enough to explain on Sullivan’s part.
After this scene plays out, Barrigan is officially labeled as the Rat in the department by Sullivan, a convenient scape goat.
So, after Barrigan kills Costigan, he and Sullivan “get into it, a scuffle, whatever” and Barrigan picks up Costigan’s gun (for some reason it’s easier to use than his own…, I don’t know why, pick a reason) kills Brown with it as he shows up out of the blue and then Sullivan disarms Barrigan and kills him with Costigan’s gun.
Since Barrigan is now officially the Rat, Sullivan can bend the narrative of the gun play in any way that works in his favor.