The Bad Lieutenant's Neighbours

From Wiki and Wiki:

The film opens in the Bronx, where The Lieutenant (Harvey Keitel) and his wife Kelly (Rose Byrne) are a young couple with two sons, which he drops off at Catholic school.

The restrictions of parenthood make it difficult for him to maintain his old lifestyle, so after his sons leave the car, and before he drives to work, the Lieutenant takes a few small bumps of cocaine.

One day, the couple finds out that Delta Psi Beta, a fraternity known for their outrageous parties, has moved next door. The Lieutenant wanders away from the scene to get some coffee, and across the street, he watches the fraternity's leaders, Teddy Sanders (Zac Efron) and Pete Regazolli (Dave Franco) rifling through the trunks of parked cars, which he ignores.

In the next scene, the detective approaches a group of drug dealers, who aspire to join Delta Psi's Hall of Fame by throwing a massive end-of-the-year party. Later, the couple visit their neighbours to ask them to keep it down, but they run off as they approach.

The Lieutenant follows them into an apartment building and up the stairs to ask them to keep the noise down. Teddy agrees on the condition that the Lieutenant gives him a bag of drugs from a crime scene.

Teddy invites them to join the party which the couple agree to. The Lieutenant quickly smokes some crack, and then sets aside a portion of the drugs for himself. Kelly bonds with Teddy's girlfriend, Brooke Shy (Halston Sage), who promises to give the Lieutenant the money she makes from selling the drugs in a few days.

The Lieutenant gets drunk and goes into Teddy’s bedroom, which includes a stash of fireworks and a breaker box that turns on their sound system, and engages in a threesome with two women...

Four months later, the Lieutenant Mac runs into Teddy, and they make amends. A car drives up beside them, and a voice yells, "Hey, cop!" before 2 shots ring out. The film closes as bystanders realise the Lieutenant has been murdered while Kelly stays home and plays with their two sons.