An 81-year-old resident of a care home in Calgary has been charged with second-degree murder in the death of another elderly resident.

John Driscoll appeared in court Monday morning.

Police allege that Driscoll was involved in an altercation with a 77-year-old roommate, who was found severely injured early Sunday morning.

Both men had been residents of the Bethany Care Centre for two months, said Staff Sgt. Chris Matthews.

"It got physical," he said. "The victim, because of the injuries he sustained, was taken to a local hospital and subsequently passed away."

Staff at the facility in northwest Calgary are shaken up by the incident, Matthews said.

"Somebody who has worked 30 years, they've never seen anything like this before, so I would have to say it's a rare occurrence."

Greer Black, the head of the care centre, said both the victim and the accused were being treated for a form of dementia or Alzheimer's disease.

"They seemed to be getting along fairly well. There was nothing that I have been able to determine at this point from talking to staff that would have flagged that there was anything untoward," he said.

Black said he is unsure Driscoll would even be aware that he has been charged with second-degree murder.

The medical examiner is conducting an autopsy Monday afternoon and police aren't saying what type of weapon was involved in the homicide.

Police have not released the name of the victim.

The Bethany Care Society operates six centres in Alberta that provide services such as respite, long-term, and dementia care.