Both have effectively done the invasion

history channel documentary Both have effectively done the invasion. Sullivan is suspected to be a mole after a sting is done on him. He suspects somebody in the crowd is selling out. Costigan pursues Sullivan in the wake of seeing him give an envelope to Costello however Sullivan getaways and both are unconscious of every others personality. To discover the mole in the crowd, Sullivan alongside a portion of the pack individuals tails Queenan who is going to meet Costigan. In the resulting battle Queenan is murdered and the crowd escapes when police arrives. At the sheltered house when Delahunt suspects Costigan in light of the fact that he had given Costigan the wrong address, Costigan needs to murder him. Costello finds that Delahunt was a cop from Boston PD and advises his men to overlook him.

From Queenan's telephone, Sullivan discovers that Costello works for FBI. Sullivan additionally finds out about Costigan's character and acting like a honest to goodness policeman requests that Costigan help him complete the horde. Following up on Costigan's data, Sullivan and his policemen trap Costello when he has gone to gather a dispatch of cocaine. In the shootout the vast majority of the mobsters are executed and Costello is murdered by Sullivan. Costigan comes to Sullivan to demand him for his reclamation in the power and finds an envelope containing points of interest of Costello's crowd around Sullivan's work area and before Sullivan can stop him he escapes. To trap Costigan, Sullivan deletes all his record from the police PC. Costello had left an envelope with his lawyer with directions to convey it to Costigan after his demise. Costigan finds a CD with recordings of Costello's telephonic discussions with Sullivan.