A teenage relative of a notorious Australian serial killer has admitted axing a friend to death and leaving the body in the same forest where his relative killed seven backpackers.
The boy, who cannot be named because he was a juvenile at the time of the killing, pleaded guilty in a Sydney court to killing 17-year-old David Auchterlonie.
David's battered body was found last year in the remote Belanglo State Forest south-west of Sydney.
His killer is a relative of Ivan Milat, who is serving a life sentence for murdering seven young backpackers between 1989 and 1992. Milat buried his victims in shallow graves in the Belanglo forest.
The youth bragged to his friends a day after killing David: "I killed somebody last night."
He, the victim and two friends drove into the forest one night and the killing and the conversation that led up to it was captured in a mobile phone video taken by one of them.
It shows the victim rolling a marijuana cigarette in the front seat when the youth, who was standing by the boot of the car, called out to him.
The boy gets out of the car to join him. The youth then swings an axe into him, accusing him of telling people he had stolen money from his own mother.
The victim tries to run away but is chased down and forced to lie on the ground. The youth continued to accuse him of spreading rumours, and then struck him on the back of the head with the axe. The sound of the axe striking the victim and the victim's last breath can be heard in the recording.
The victim's father, also called David, said his son was "a character" who was always getting into trouble.
"Just a general teenager doing what silly kids do," the elder Mr Auchterlonie said. "It's been nearly a year since his death. I'm sure he would've grown out of his ways and maybe these kids as well."
The killer will be sentenced in December.