A teenager facing trial for murder was recorded in phone conversations from detention saying he had punched Mandurah sailmaker Tauri Litchfield and "put him to sleep" before he took off and fell from a wall.
The 14-year-old, who is facing trial in the Perth Children's Court with four other teenagers who have all pleaded not guilty to Mr Litchfield's murder, was also recorded complaining that other boys who were present at the incident were "going witness".
He described one of the boys as a "dog", saying he had considered bashing him, but he was only a "little kid".
Ten monitored telephone calls between the boy, relatives and friends were played to Children's Court president Judge Denis Reynolds this morning.
In several of the calls, the teenager laughs when talking about the altercation that prosecutors say led to Mr Litchfield's death.
"I only hit him once and then he was out," the 14-year-old said in a call from detention units in Hakea Prison in May last year.
In other calls, the boy said, "I put him to sleep," and claimed he "never did f... all" apart from hitting Mr Litchfield once.
The teenager was heard saying that Mr Litchfield slapped him and he responded by punching him in the jaw.
In one call, the teenager said he should only have been charged with assault.
The five boys, aged 14 to 16, are accused of chasing Mr Litchfield on Pinjarra Road on March 17 last year.
A murder charged against a 6th boy was dropped last week.
The 14-year-old is alleged to have been attempting to pickpocket Mr Litchfield when the sailmaker reacted by slapping him in the back of the head.
The teenager is accused of retaliating by punching Mr Litchfield in the jaw with enough force to knock him off his feet.
The prosecution case alleges that after Mr Litchfield got to his feet, he fled and was chased by the group before falling from a wall and striking his head on a bitumen carpark.
The court has been told the 28-year-old died later the same night after suffering non-survivable traumatic brain injury.
In a telephone call between another of the accused boys and his cousin, the 16-year-old says he "only hit" Mr Litchfield once.
In another recorded call with a 15-year-old accused boy, his mother suggests Mr Litchfield "done it to himself" by failing to stop his fall.
The trial continues.