Police suspect Wednesday's double murder-suicide in Mililani Mauka was triggered by a mental condition based on a letter and notes found at the scene.

An autopsy determined Grineline "Elaine" James, 39, died from asphyxia due to strangulation and Michael James II, 7, from asphyxia due to drowning and that both were murdered while Michael James, 43, committed suicide and died from asphyxia due to hanging.

The woman was killed sometime last weekend and the boy several days later. The autopsy listed blunt force trauma to the head as "other significant injuries" for both.

Michael James hung himself Wednesday before noon, police said.

Prescription drugs, a letter and notes found in the house at 95-1042 Mo'ohele Street indicate Michael James suffered from a psychiatric condition, police said. In a letter sent to friends and relatives, James mentioned "hearing voices" but not any other family-related or financial problems, police said.

Investigators believe the murders were directly related to his mental condition, police said.