Edmonton police are investigating what they are calling a homicide on the psychiatric ward of the Royal Alexandra Hospital.

Police, called to the hospital by staff who broke up an altercation early Monday morning, took a 34-year-old male patient into custody. His roommate, 57-year-old Dwayne Roger Roy, was pronounced dead shortly after police arrived at 3:50 a.m.

No staff members were injured.

Homicide detectives have been called in to investigate at the 678-bed hospital.

Dr.P.J. White, head of psychiatric care for Capital Health, said the two patients didn't have a history of conflict. The man taken into custody was deemed "relatively stable" and was about to be discharged, he said.

"It is a tough situation and we clearly have had a tragedy in one of our units this morning, and one of our patients obviously was killed and this to us is very serious," he said. "It's a tragedy, not just for the patient, but also for the patient's family."

Counselling is available for the staff and the 20 patients in the ward, he said.

Police say the cause of death will be determined by an autopsy, but early reports suggested thepatient had been stabbed.

The lasthomicide in a Capital Health-run facility was at Alberta Hospital in 1994.