Western Australia's Corruption and Crime Commission is investigating the death in custody of a 16 year-old Indigenous boy after receiving an allegation of serious misconduct within the facility in which he was detained.

The teenager was found unresponsive in Unit 18, a stand-alone youth detention facility within Casuarina prison, a maximum security adult prison in Perth, on 12 October.

On Friday morning it emerged life support had been switched off Thursday night.

A candlelight vigil was held for the teenager at Perth's Wellington Square Park on Wednesday evening. The ABC reported earlier on Wednesday that the the boy's suicide attempt came 12 hours after he was told his bail hearing had been delayed for at least the third time.

Additionally, a coronial inquest is mandatory in the event of any death in custody.

Last week WA Premier Roger Cook described Unit 18, which has been at the centre of controversy since it was introduced in July 2022, as a "necessary evil".

58 letters from detainees detailing abuse allegations from both Unit 18 and Banksia Hill Detention Centre were tabled in WA parliament in May.

A class action involving hundreds of former WA youth detainees, among which Indigenous youth are drastically over-represented, is currently underway.

More than 500 Indigenous people have died in custody since the Royal Commission into Aboriginal Deaths in Custody brought down its findings and more than 300 recommendations in 1991.

National Indigenous Times has contacted Western Australia's Department of Justice and Western Australian Minister for Aboriginal Affairs, Dr Toni Buti, for comment.

A Justice spokesperson said on Friday that department "wishes to express deepest sympathies to the boy's family, friends and community for their tragic loss".

More to come.