During the 1980s Michael Dowd worked the meanest possible streets of New York as a patrolman with NYPD’s 75th division. There were 100 murders in one year in Dowd’s five-square-mile precinct. Crack cocaine was everywhere and calls just kept coming over the radio. It was, by Dowd’s own account, “the land of fuck”.

By 1993, the same cop was testifying before the Mollen Commission, a body created to investigate police corruption. He admitted to hundreds of crimes, including theft, extortion, drug use and narcotics rackets. When asked by the committee if he considered himself to be a cop or a drug trafficker, he answered: “Both.” The tabloids called him “New York’s dirtiest cop”. And worse.

Using talking head testimony and old archival images, Tiller Russell's film charts Dowd's rise and fall with a momentum close to the breakneck speed of the last half-hour of Goodfellas. It is a flabbergasting chronicle of corruption that begins with Dowd tearing up a speeding ticket and ends with him driving a Corvette to work.

Dowd’s account to camera of his misdeeds is every bit as audacious as his criminal acts. A born raconteur, he pulls the viewer in just as he did to his various accomplices, including Adam Diaz, a Dominican drug lord who speaks in fluent Scarface-ese.

It is perhaps a shame the film’s good guys, including the Suffolk County police who finally swooped in on Dowd, aren’t as charismatic as the villains. In the end, the corruption and the culture of silence that protected it are not the most terrifying things about this thrilling documentary: it’s the fact most viewers would happily enjoy a pint with the perpetrator.