The Departed is a 2006 American crime thriller film[3][4][5] directed by Martin Scorsese and written by William Monahan.

[7][8][9] The film stars Leonardo DiCaprio, Matt Damon, Jack Nicholson, and Mark Wahlberg, with Martin Sheen, Ray Winstone, Vera Farmiga, Alec Baldwin, Anthony Anderson and James Badge Dale in supporting roles.

Irish Mob boss Frank Costello (Nicholson) plants Colin Sullivan (Damon) as a spy within the Massachusetts State Police; simultaneously, the police assign undercover state trooper Billy Costigan (DiCaprio) to infiltrate Costello's mob crew.

Many years later, Sullivan has been groomed as a spy inside the Massachusetts State Police (MSP) and joins the Special Investigation Unit (SIU).

Another police academy recruit, Billy Costigan, is selected by Captain Queenan and Sergeant Dignam to go undercover as a criminal and infiltrate Costello's crew.

A news report reveals that Delahunt was a Boston Police Department undercover officer, but Costello suspects it is a false claim so he would stop looking for the mole.

Upon reaching the lobby, Costigan is shot dead by Trooper Barrigan, a friend of Sullivan's who is another of Costello's spies.

The final shot shows a rat crawling on the rail of the patio with the Massachusetts State House in the distance.

[14][8][15] In March 2004, United Press International announced that Scorsese would be remaking Infernal Affairs and setting it in Boston, and that Leonardo DiCaprio and Brad Pitt were slated to star.

[8] A technical consultant on the film was Tom Duffy, who had served three decades on the Boston Police Department, particularly as an undercover detective investigating the Irish mob.

For budgetary and logistical reasons many scenes, in particular interiors, were shot in locations and sets in New York City, which had tax incentives for filmmakers that Boston at the time did not.

Film critic Stanley Kauffmann said that for The Departed, Scorsese "was apparently concerned with the idea of identity, one of the ancient themes of drama, and how it affects one's actions, emotions, self-knowledge, even dreams."

[23] Film critic Roger Ebert compared Costigan and Sullivan's seeking of approval from those they are deceiving to Stockholm syndrome.

Scorsese acknowledges that while it is not meant to be taken literally, it somewhat symbolizes the "quest for the rat" in the film and the strong sense of distrust among the characters, much like post-9/11 U.S.

Dignam, the lighted "X" on the wall in Sullivan's office when he assures Costello over the phone that Costigan is not the rat, the taped windows of the building Queenan enters before being thrown to his death, behind Costigan's head in the elevator before he is shot, and the carpeted hallway floor when Sullivan returns to his apartment before being shot by Dignam at the film's end.

The site's critics consensus reads, "Featuring outstanding work from an excellent cast, The Departed is a thoroughly engrossing gangster drama with the gritty authenticity and soupy morality we have come to expect from Martin Scorsese.

"[29] On Metacritic, the film has a weighted average score of 85 out of 100, with 92% positive reviews based on 39 critics, indicating "universal acclaim".

[24] Online critic James Berardinelli awarded the film four stars out of four, praising it as "an American epic tragedy."

He went on to claim that the film deserves to be ranked alongside Scorsese's past successes, including Taxi Driver, Raging Bull and Goodfellas.

[36] A few critics were disappointed in the film, including J. Hoberman of the Village Voice, who wrote: "Infernal Affairs was surprisingly cool and effectively restrained for HK action, but Scorsese raises the temperature with every ultraviolent interaction.

Mark Wahlberg was also nominated for the Best Supporting Actor award for his performance, but he lost to Alan Arkin for his role in Little Miss Sunshine.

The second disc contains deleted scenes, a feature about the influence of New York's Little Italy on Scorsese, a Turner Classic Movies profile, a theatrical trailer, and a 21-minute documentary titled Stranger Than Fiction: The True Story of Whitey Bulger, Southie and The Departed[47] about the crimes that influenced Scorsese in creating the film, including the story of James "Whitey" Bulger, upon whom Jack Nicholson's character is based.

The film score for The Departed was written by Howard Shore and performed by guitarists Sharon Isbin, G. E. Smith, Larry Saltzman and Marc Ribot.

[50] Scorsese described the music as "a very dangerous and lethal tango" and cited the guitar-based score of Murder by Contract and the zither in The Third Man as inspiration.