Where does Costigan die in "The Departed"?

Costigan dies in the elevator in Martin Scorsese’s “The Departed.” After arresting Colin Sullivan on the rooftop, Billy Costigan escorts him toward the lobby, but Trooper Sean Barrigan suddenly shoots Costigan in the head as the elevator doors open.

The killing is a final revelation: Barrigan is another corrupt Massachusetts State Police officer secretly working for mob boss Frank Costello. He then shoots Costigan’s police colleague, Brown, before Sullivan kills Barrigan and conceals the extent of the conspiracy.

The scene is often confused with Captain Queenan’s death earlier in the film. Queenan is thrown from a building after helping Costigan escape, while Costigan is killed at the elevator. The abrupt death also mirrors the shocking structure of the Hong Kong film “Infernal Affairs,” on which “The Departed” is based.