B.C.'s police watchdog is investigating after Mounties used a Taser during the arrest of a Chilliwack woman over the weekend.

Mounties said officers were called to a home on Paula Crescent at around 2 p.m. Sunday for a report that someone's roommate had taken their vehicle without consent. While police were at the residence, the roommate came back home.

The woman allegedly threatened police with some type of weapon when they entered the home, the RCMP said in a statement the next day.

Mounties said they attempted to de-escalate the situation, but ultimately were unsuccessful. A Taser was used to take the woman into police custody, and she was injured in the process.

The Independent Investigations Office said it appeared that she fell down some steps after the Taser was deployed. Her injuries are serious but are not believed to be life-threatening, the IIO said in a statement.

The watchdog was called to investigate whether there is any link between her injuries and police actions. The IIO is called in all cases of officer-related incidents involving death or serious harm to determine whether offences were committed.

The original complaint about the vehicle is currently under investigation by the RCMP's Upper Fraser Valley Regional Detachment.