The Bill - Season 11 Episode 36 Hair Trigger
Overview: Deakin investigates the fatal shooting of a mother by her teenage son, who claims that the incident was a pure accident, as the gun had a hair trigger, which caused it to go off when the boy backed into a wall. However, with the gun having also been previously used in an armed robbery, Deakin soon realises that the boy's relatives may let him face a murder charge in order for them to get away with their own crimes.