A 95-year-old grandmother who Australian police tasered at a retirement home is in critical condition as the homicide squad join a high-profile investigation into the incident, police said on Friday.

Police were called to the Yallambee aged care home in Cooma, about 300 km (186 miles) southwest of Sydney, on Wednesday after staff found resident, Clare Nowland, outside her room holding a steak-knife, New South Wales police assistant commissioner Peter Cotter said.

Two officers spoke with Nowland for several minutes but when she failed to drop the knife and approached them, one fired a taser, knocking her to the ground.

“At the time she was tasered, she was approaching police but it is fair to say at a slow pace,” Cotter said during a press conference. “She had a walking frame, but she had a knife.”

Nowland, who suffers from dementia, had wandered the facility for several hours and taken the knife from the kitchen.

She is in a critical condition in hospital, fading in and out of consciousness, sparking a public uproar over the incident.

“The use of a taser when a kind word was all she needed … she was confused which is what happens with people who have dementia, she needed kind words and assistance and help. She didn’t need the force of the law,” community advocate Andrew Thaler told Reuters.

The officer who fired the taser was off duty pending a “level 1 critical incident investigation”, a category police reserve for exceptional cases where injuries lead to death or imminent death. The homicide squad is involved.

“If a threshold is met where it changes from being a departmental issue to being a criminal issue, we are certainly mature and transparent enough as an organisation to do what has to be done,” said Cotter.

Body cameras recorded the encounter but it was not in the public interest to release the footage because of the investigation, he said.