‘The Departed’ explained: how did Dignam know Sullivan was the rat?
There was an outpouring of joy and relief in the industry when The Departed finally snagged Martin Scorsese that elusive Academy Award for ‘Best Director’ at the sixth time of asking, in what was his eighth nomination in total.
He’s racked up another eight nods since then, and while the labyrinthine crime thriller isn’t held up by many as his best-ever feature, there’s no shame in that when Scorsese has been responsible for a handful of the greatest films ever made.
The ‘Best Picture’ winner told a sprawling, epic story that operated on both sides of the law, weaved them together, and then brought each of them crashing down through a string of twists, turns, and revelations that even left audiences unsure who to trust.
It was a master at work making a star-studded, crowd-pleasing genre film that reaped huge critical and commercial rewards, but that doesn’t mean every plot point was resolved in an inarguably definitive fashion.
What is The Departed about?
A remake of 2002 Hong Kong classic Infernal Affairs, The Departed also drew its inspirations from the Boston Winter Hill Gang, with Matt Damon’s Colin Sullivan and Jack Nicholson’s Frank Costello indebted to the real-life dynamic between corrupt FBI agent John Connolly and crime boss Whitey Bulger.
Leonardo DiCaprio’s cop Billy Costigan is sent deep undercover to infiltrate Costello’s criminal empire, at the same time, the underworld figurehead’s protégé Sullivan works his way up the ranks of the local police department, with the respective organisations both suffering from a rat infestation.
Working on opposite sides of the law unbeknownst to almost everyone around them, bar a select few, subterfuge and close calls find Costigan and Sullivan getting increasingly close to discovering each other’s real identities, set against the simmering backdrop of Boston’s illicit operations.
What happens at the end of The Departed?
After realising who the other one is, Sullivan tries to cover his tracks and remove Costigan from the equation, although the latter has already exposed the rat ahead of time by handing an incriminating envelope to Vera Farmiga’s Madolyn Madden.
Costigan and Sullivan meet on a rooftop, where the latter is arrested. He’s not in handcuffs for long, though, with James Badge Dale’s Trooper Barrigan revealing himself as another mole of Costello’s, who guns down Costigan before being taken out by Sullivan to cover his tracks.
Thinking he’s got away scot-free, Sullivan gets a nasty surprise when Mark Wahlberg’s Sean Dignam is waiting for him, brandishing a firearm and dressed like a man planning not to leave behind any evidence that he was there. He shoots Sullivan in the head, vacates the premises, and a rat fittingly runs across the screen before the credits roll.
How did Dignam know Sullivan was the rat?
It’s never explicitly spelt out how Dignam found out Sullivan was working for Costello all along, but the easiest conclusion to reach is that it was Madolyn’s doing. She was in possession of the tapes handed to her by Costigan, which could have been easily passed along to an officer not only determined to do the right thing and willing to bend the limits of legality in achieving it but also seek revenge for the murder of Martin Sheen’s Charlie Queenan.
The other interpretation is that Dignam was also a rat, of sorts at least. Costello was confirmed to be an FBI informant, but it’s never explained who he reports to or how he gets in contact. That creates the possibility that Dignam was the middleman between the crime boss and the federal authorities, with Sullivan’s execution eliminating one of the last remaining loose ends that could reveal his duplicity.
