1999 film by Johnnie To

2016 Hong Kong film

To take down South Boston's Irish Mafia, the police send in one of their own to infiltrate the underworld, not realizing the syndicate has done likewise. While an undercover cop curries favor with the mob kingpin, a career criminal rises through the police ranks. But both sides soon discover there's a mole among them.

2012 film directed by David Ayer

Five police officers in Hong Kong are kidnapped. The police commissioner is on a business trip overseas. Two vice commissioners, Sean Rau and M.B. Lee, then take over the case. The two vice commissioners are rivals who both vie for the police commissioner seat. At first, M.B. Lee takes the lead in the case, but comes to a dead end. Sean Lau then takes the lead, but he falls into a trap. Both men are then investigated by the ICAC (Independent Commission Against Corruption).

Champion competitive marksman Ken comes across an armored van robbery. He sees a policeman held hostage and shoots and kills four of the robbers. One of the robbers escapes and the policeman survives. The case is handled by Jerry Chang, whom Ken knows from having recently beaten him in a shooting match. Ken is found not guilty in court. Soon after, Ken is attacked by the escaped robber Pang Tao. Their confrontation reveals a very different background story and brings about a myriad of lies and traps and changes in relationships as Jerry and Ken try to outsmart each other.

Set in the ghettos of Paris in 2010, an undercover cop and ex-thug try to infiltrate a gang in order to defuse a neutron bomb.

Former London constable Nicholas Angel finds it difficult to adapt to his new assignment in the sleepy British village of Sandford. Not only does he miss the excitement of the big city, but he also has a well-meaning oaf for a partner. However, when a series of grisly accidents rocks Sandford, Angel smells something rotten in the idyllic village.

Detective Sergeant Ma Jun, known for dispensing his own brand of justice during arrests, teams up with an undercover cop, Wilson, to try and bring down three merciless Vietnamese brothers running a smuggling ring in the months before mainland China's takeover of Hong Kong. Jun pursues the gang tirelessly, sometimes ignoring police protocols. A showdown is inevitable!