The teenager accused of murdering a mother and her two children was at a public hospital in Midland hours before their deaths, according to sources.

Teancum Vernon Petersen-Crofts has been charged with three counts of murder. Credit:Facebook

Teancum Vernon Petersen-Crofts, 19, presented at St John of God Midland public hospital emergency department in a "psychotic state" on Saturday.

WAtoday understands Mr Petersen-Crofts was behaving erratically, but his condition was not considered to be a “medical problem”.

A source said he was taken to the Brixton Crescent home just hours before three family members were found dead on Sunday morning.