As we now cope with the latest problem with policing in America — the overt militarization of local forces that has made cops see civilians as “the enemy” — let us look back on the last big wave of corruption in law enforcement via the biggest scandal in the history of the NYPD. In 1992, officer Michael Dowd, called by some the dirtiest cop ever, was arrested after it was discovered that he had turned the 75th precinct in East New York, Brooklyn, into his own personal gangland, selling drugs, setting dealers on one another, and extorting protection money from just about everybody… and that he’d been doing this for years. Documentarian Tiller Russell has assembled a Scorsese-esque examination — one that is fascinating in a horrifying sort of way — of how Dowd and his partner, Kenny Eurell, ran their operation, and how the lax culture of the NYPD at the time, which didn’t take integrity seriously, created a fertile breeding ground for such outrageous criminal activity by those sworn to protect and serve the public, not themselves. Dowd was far from the only cop behaving this way, as the citywide investigation known as the Mollen Commission uncovered at the time, and Russell deftly interweaves Dowd’s testimony to that commission with new interviews with Dowd and Eurell, along with stark black-and-white photos from the era, to create a riveting portrait of official authority and toxic masculinity gone way off the rails. The film leaves some important questions unanswered: Eurell’s wife is interviewed but not Dowd’s; where is she? Were either of their wives prosecuted for their involvement? And why isn’t Dowd still in prison, or did he even go to prison at all? (We do learn that Eurell made a deal with the feds to turn on Dowd.) But mostly, this is a necessary peek into a secretive subculture — cops! — that many people don’t even think of as a secretive subculture.