Johnny Depp plays South Boston thug Whitey Bulger, whose four decade crime spree is a case study of political and law enforcement corruption. (Photo: Warner Bros)

Johnny Depp plays South Boston thug Whitey Bulger, whose four decade crime spree is a case study of political and law enforcement corruption. (Photo: Warner Bros)

Johnny Depp returns to form in “Black Mass,” the stylish, sinewy story about infamous gangster Whitey Bulger. His criminal exploits were at the epicenter of corruption, drugs, extortion and murder in South Boston for four decades.

The film is already drawing comparisons to Marty Scorsese’s 2006 classic, “The Departed.”

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The gritty, awe-inspiring Scorsese film, starring Leonardo diCaprio, Matt Damon, Jack Nicholson Mark Wahlberg and Martin Sheen, won Oscars for Best Picture, Best Director, Best Adapted Screenplay and Best Film Editing at the 79th Academy Awards.

Whatever damage Johnny Depp has done to his career with bombs like “The Lone Ranger,” “Transcendence” and “Mortdecai,” he more than makes up for here. His performance is nuanced, economical and winning.

“Black Mass” could land Depp in solid Oscar contention along with stellar performances from Joel Edgarton, Kevin Bacon, Rory Cochrane and Benedict Cumberbatch.

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Director Scott Cooper keeps the focus on the story and keeps it moving in a brisk, workmanlike fashion.

Cumberbatch, as the battered and conflicted brother, at times, lets his English accent slip through. Nonetheless, he’s stellar.

Bacon and Cochrane, who I well remember from “CSI Miami,” also shine in their roles.

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Dakota Johnson, whose role is never quite explained, appears to be Bulger’s one-time wife/mistress. After their sons dies unexpectedly, she suddenly disappears. A Bulger murder victim?

The film, itself, begins with an epilogue. A series of one-time Whitey Bulger thugs talk about their plea deals and tell what really happened.

Bulger survives so long because of his political and law enforcement connections. His brother was a celebrated Massachusetts State Senator and Bugler worked as an FBI informant.

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He deftly plays the agency, feeding it information on his chief rival, the Boston Mafia under Raymond Patriarca. The FBI is more interested in Patriarca than Bulger’s Irish-American gang. So, agents turned a blind eye to his criminality.

Bulger’s seemingly-simpatico FBI cohorts keep him out of harm’s way and on the street for years. Along the way, they slowly become corrupted. In fact, Bulger’s FBI handler tipped him off about his pending indictment, allowing him to flee.

Bacon plays Charles McGuire, a cop who wonders why everyone but Bulger gets stung. Stoll, as prosecutor Fred Wyshak, eventually enlists his own investigators and starts taking down the Bulger crew, one-by-one.

Edgarton, who plays Bulger’s childhood friend and FBI handler John Connolly, unquestionably delivers the film’s strongest performance. He’s a good-guy-turned-bad, who parties and hangs with Bulger like he’s one of his crew.

The two immediately understand their roles, and Connolly’s seduction is fascinating to watch. Connolly is ultimately arrested by two FBI agents in a heart-wrenching scene.

The FBI agent really wanted to do good, but he was dragged down by his fascination with Bulger’s gangster lifestyle.

Bulger fled Boston when his criminal enterprise began to unravel in 1994. He spent the next 16 years on the lam.

At times he was No. 2 on the FBI’s Most Wanted List behind only Osama bin Laden. He was finally arrested in 2011. Now 86, he’s serving two life sentences in a federal pen in Florida.

In the final scene of the movie, Depp’s Bulger is sitting in a church. He knows what he’s done.

In the annals of great gangster films, “Black Mass” is a must-see.

The film opens Friday (Sept. 18).

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