The death of a 55-year-old woman Monday who was in Edmonton police custody is under investigation by the Alberta Serious Incident Response Team.

Officers called to the Belvedere LRT station on Sunday encountered three intoxicated people, ASIRT said in a news release Tuesday.

They arrested the woman, charging her with causing a disturbance and breach of recognizance.

She was also arrested on outstanding warrants for theft and for failing to appear. 

The woman was placed in a holding cell with other people. During a cell check at around 10 a.m. the next morning, the woman was found on the floor unresponsive and having difficulty breathing.

ASIRT said there were no obvious signs of significant trauma or injury.

The woman was taken to hospital in critical condition and died Monday evening. An autopsy is scheduled for Wednesday.

The investigation will focus on whether police conduct caused or contributed to the woman's death, the release said.

ASIRT investigates incidents involving police that result in serious injury or death, as well as allegations of police misconduct.