POLICE KILLING is a documentary about homicides committed by on duty police officers in Rio de Janeiro, in situations initially considered as legitimate self-defense. The dead person is accused of being a drug dealer and having fired against the police. However, the officers' account is confronted by the emergence of videos and the fight of mothers who try to prove their sons were innocent. The film portrays the clash of versions in court hearings, the backstage of police investigations and the State Parliamentary Inquiry Committee established to investigate the high rates of homicides during police operations.