Accused teenage murderer Teancum Vernon Petersen-Crofts has a long history of mental health issues, his father has confirmed.
Awatea Crofts said his son had been admitted to several mental health facilities in the past - but had never received the appropriate medical help, ABC News reports.
Even throughout this year, his son was in and out of mental health facilities and recently his condition had declined.
Petersen-Crofts appeared in a Perth court on Monday after being charged for the death of his mother, Michelle Petersen, 48, her daughter Bella, 15, and son Rua, 8.
The bodies of his mother and Rua were discovered inside their Ellenbrook home on Sunday. Bella was found critically injured in the backyard. She died on the way to hospital.