An inquest into the death of a Perth woman who took her own life in Mexico has heard she was discharged from hospital despite staff finding a suicide plan in her room.
The 39-year-old, known as Ms D, was involuntarily admitted to Perth's King Edward Memorial Hospital while suffering from severe post-natal depression in 2008.
She had also borrowed a library book about euthanasia.
Despite that, she was released from hospital without her family's knowledge.
The Mental Health Review Board put her into the care of Fremantle's Alma Street Clinic.
The board allowed her to become a voluntary patient and she discharged herself.
Three weeks later Ms D travelled to Mexico and took her own life using a euthanasia drug banned in Australia.
Her husband has told the inquest that the mental health system let her down.
Her estranged husband told the court he could not believe she had been released and feels the hospital did not use its powers to protect her.
The woman's sister will give evidence this afternoon.