Fed up with violent behaviour at a block of public housing flats so notorious it was nicknamed The Bronx, Christopher James Marshall decided to "take a stand" when he fatally stabbed a drunk man in the back five times with a broken golf club.
Details of the killing emerged in the Supreme Court yesterday after Marshall pleaded guilty to a charge of manslaughter over the death of 23-year-old Quentin Cornwall on January 25 last year.
Marshall, in his early 30s, was originally charged with murder and due to face a trial earlier this year before prosecutors accepted his guilty plea to the lesser charge on the basis that he had used excessive force in defending himself and his home.
Marshall was having birthday drinks with other residents at the block of flats in the Bunbury suburb of Withers when Mr Cornwall arrived with two associates in search of another man he wanted to fight.
Prosecutor Louise O'Connor said Marshall was trying to calm the situation after Mr Cornwall, who had a blood alcohol level of 0.316, confronted the other man.
Marshall retreated to his unit after Mr Cornwall became aggressive. Mr Cornwall then ripped the flywire from the security screen at Marshall's front door and armed himself with a broken leg from a chair.
Marshall then armed himself with the golf club, leaving the shaft embedded in Mr Cornwall's back after stabbing him so deeply it penetrated close to the width of his body.
He told police he felt threatened and scared, but admitted he had "lost his mind" and wanted to "take a stand" after previous incidents of violence at the units.
Lawyer Richard Utting said his client was in a car accident when he was 17 and had a frontal lobe brain injury, which affected his impulse control and judgment.
Supreme Court Commissioner Kevin Sleight said the case involved some complexity. He will sentence Marshall on Friday.