The woman was taken into custody in Port Alberni on Feb. 15 after RCMP officers determined she may have not been compliant with a court order.
But the Independent Investigations Office says she suffered a leg injury during her arrest and was assessed by the BC Ambulance Services in police cells before being transferred to hospital.
The police watchdog says it began looking into the event because of information it received one week after the incident.
The agency says it forwards reports to prosecutors when its chief civilian director believes an officer may have committed an offence, although the report includes no recommendations on charges.
The police watchdog says Crown counsel will now determine whether an offence occurred and whether if can be proven in court beyond a reasonable doubt.