WA man pleads guilty to killing baby

A 24-year-old man has pleaded guilty to unlawfully killing his baby daughter at their Perth home.

Seven-month-old Lily was found unconscious at the Ellenbrook house in September last year and died in hospital from head injuries.

Paul James Cosgrove appeared in Stirling Gardens Magistrates Court on Wednesday via video link from prison and pleaded guilty to manslaughter.

Family members wept in court during proceedings and one woman yelled: "You low life piece of scum!"

A pre-sentence, psychological and psychiatric report has been ordered ahead of Cosgrove's sentencing hearing in the WA Supreme Court in December.