PORTLAND, Ore. (KOIN) — A man was charged Thursday for the murder of his mother in October, according to Portland police.

Authorities said on Thursday afternoon that the mother’s cause of death was homicide by manual strangulation.

On October 20, just before 7:30 a.m., officers responded to a death investigation call at a house in the 5500 block of Southwest Menefee Drive in the Hillsdale neighborhood. The Multnomah County Medical Examiner was already on scene and the officers assisted with the investigation into the death of the victim, identified as 59-year-old Teresa Graham. At that point, authorities reported no sign of foul play.

However, officials say that the following day, the ME’s office notified police that the autopsy revealed “suspicious circumstances,” and the investigation continued.

This led to the arrest of Graham’s son, 27-year-old Austin Graham. He was booked into the Multnomah County Detention Center on a charge of second-degree murder-domestic violence, authorities say.

This is an active investigation and if anyone has information about this case, they are encouraged to contact Portland police.