Geraldine Beardy, 29, died Sept. 18 after lapsing into a coma. Police are investigating her death on suspicion she was assaulted. (CBC)

Winnipeg police are investigating the possibility a 29-year-old woman who died after being assaulted was attacked in a case of vigilante justice, CBC News has learned.

Geraldine Beardy, of Garden Hill First Nation, was taken off life support at a city hospital Friday, her mother, Louise Keno said Monday.

One of the last places Beardy was seen was at a grocery store on Sherbrook Street on Sept.13, almost a week before she died, police said Saturday.

Justice sources said Winnipeg police are investigating whether the woman was attacked by someone working at the store after she tried to steal a can of lunch meat worth $1.49.

After she died Friday, police returned to the store the same day. The store remained closed for the day with a cruiser car parked outside.

Police have not said publicly where they believe Beardy was assaulted.

Keno said her daughter, a mother of three, was hit with a bat. She lapsed into a coma after being assaulted.

CBC News has spoken to the owner of the store where Beardy was accused of shoplifting.

The owner confirmed the attempted theft, but said he asked Beardy to leave. He said he didn't know what happened to her after that.

Keno said Beardy was ill and needed to be in Winnipeg for medical treatment. She did not have a fixed address in the city but had been there since June.

The family is making funeral arrangements. Keno said she hoped to take Beardy's body back to Garden Hill this week.