The province's Special Investigations Unit has decided to probe an  incident involving Niagara police.

Officers went to a St. Catharines address early yesterday morning regarding a domestic dispute.

The caller advised police a female was armed with a knife and threatening to hurt herself.

The woman suffered self inflicted injuries while police were on the scene.

She was taken to hospital with life threatening injuries.

No other details will be released while the SIU investigates.