“The Seven Five,” an engrossing documentary about extreme corruption in the New York City Police Department during the 1980s and early ’90s, could be the crime drama Martin Scorsese wishes he’d made. Or may yet make.

The documentary’s memorable real-life characters include drug dealers, NYPD internal affairs investigators, federal agents and the dirty cops. The bad cops and dealers tell their over-the-top exploits to director Tiller Russell with vivid detail. They also throw four-letter words around as if they really are in a Scorsese movie.

Michael Dowd, a former NYPD officer who served 12 years in prison for racketeering and conspiracy to distribute narcotics, is the film’s main character.

“My dreams are about being a good cop,” he tells Russell in post-prison times. “Sad, though. Never happened.”

“The Seven Five” principally chronicles the bad cop things Dowd and his partner, Kenneth Eurell, did while they were charged with serving and protecting the largely impoverished residents who lived in the crime-plagued 75th Precinct of East New York.

Russell uses a Mollen Commission hearing Dowd gave testimony to as a reference point throughout the film. The commission investigated police corruption in the NYPD.

With nothing left to lose, Dowd spoke frankly. One commissioner asks, “Did you consider yourself to be a New York City police officer or a drug trafficker?” Dowd hesitates before replying, “Both.”

The film sets the scene for the early ’80s era during which Dowd and Eurell, then in their early 20s, became cops. New York City was experiencing a crime wave of homicides, drug dealing and cop killings. Dowd and Eurell were assigned to the city’s most dangerous precinct.

Russell and his interviewees explain the police culture that made it OK for officers to look the other way if a cop was dirty. As the terminology went, those who didn’t rat on their brother police officers were “good” cops.

In that atmosphere, Dowd felt invincible. “I never had fear of getting busted, because the cops around me would never give me up,” he says.

Eurell says he only reluctantly became Dowd’s partner. Dowd already had a bad reputation. He was a mad man. But once Dowd showed Eurell how much money could be made by stealing from criminals, the seduced Eurell became a full participant.

Drug dealers Baron Perez (his Auto Sound City car stereo shop served a front for cocaine) and Adam Diaz, a major dealer from the Dominican Republic (his grocery stores were fronts for cocaine), flesh the story out with supporting, fascinating details.

The wry, smiling Diaz, who’s since been deported to the Dominican Republic, is as interesting as any fictional gangster in a feature film. And Diaz and Dowd come off as loyal brothers in crime. Diaz affectionately expresses his huge admiration for the criminal cop.

Russell shapes this true-crime narrative with the energy and action of a great gangster movie. Despite being a documentary, “The Seven Five” can be watched alongside any great gangster movie. And the New York accents are legit.