Vancouver health authorities have launched two separate reviews after an 81-year-old man was killed in a residential care home on the University of British Columbia campus.

The senior, whose identity hasn't been released, is believed to have been involved in an altercation with a 71-year-old man at the Purdy Pavilion last Wednesday.

He was taken to hospital in deteriorating condition, and died the following day.

Apart from the two internal reviews being conducted by health officials, the Integrated Homicide Investigation Team confirmed it has launched a probe into what happened.

Few details have been confirmed, but Cpl. Meghan Foster said investigators hadn't gathered enough evidence to support criminal charges by Tuesday afternoon.

"No one is in custody, and no charges have been laid. This is an isolated incident, and there are no concerns relating to public safety," Foster said in a statement.

Purdy Pavilion is a long-term residential care facility operated by Vancouver Coastal Health that cares for more than 200 patients, most of them elderly, on four floors. The majority of residents have cognitive impairments and require 24-hour care.

The B.C. Nurses' Union said it can't comment on last week's incident specifically, but suggested similar episodes of aggression among residential care patients are on the rise – and that better staffing could make a difference in how they play out.

"If the appropriate levels of staffing were in place we could sit down and calm that patient. We could tend to the sundowning episodes these patients have," union president Gayle Duteil said. "But right now, with bare bones staffing across the province it's challenging to do."

Security guards are also urgently needed in these facilities, she added.

"I can assure you in almost every residential care facility there is zero security. There aren't even panic alarms for nurses," Duteil said.

Vancouver Coastal Health described the incident as a tragedy, and said it is conducting two internal reviews into what happened.

IHIT said unless further evidence comes to light or charges are approved, it won't be releasing more information on the case.

With files from CTV Vancouver's St. John Alexander