A judge in Australia took the unusual step of releasing video footage of a teenage killer shot in the moments after he had blasted a youngster to death while out of his mind on drink and drugs.

Rambling incoherently and slipping in and out of conciousness, 17 year-old Liam Humbles was captured on tape with blood smeared on his face from his crime, soon after he killed 18 year-old Lewis McPherson.

Humbles, now aged 19, was jailed in Adelaide, Australia, for 24 years for shooting dead Lewis McPherson in 2012.

He claims he still cannot remember gunning down his victim because he was so high when it happened.

Humbles blasted McPherson with a pistol which he claimed he carried around with him for protection from bullies.

After blasting his victim, Humbles fired at two of the victim's pals, Liam Trewartha and James Lamont. The court ruled he had intended to kill them too.

Jailing Humbles for 24 years, Judge Michael David also lifted a ban on the killer – now aged 19 – from being identified. It meant the video could be shown of the aftermath of the bloody slaying and Humbles' own intoxication.