B.C.'s police complaints commissioner has ordered an investigation into the Victoria Police Department after a teenage girl alleged she was beaten and tethered to a door while she was drunk in a cellblock.

Dirk Ryneveld said he will order another police department to investigate what happened to Willow Kinloch, who was 15 at the time and is now suing the police alleging that officers unlawfully confined her and assaulted her.

"I need to ensure that there is confidence in both the police and the police complaint process," Ryneveld told CTV's Jim Beatty. "I believe that can only be accomplished in this case by an external investigation."

Surveillance tape shows officers pushing Kinloch against the wall of a jail cell, forcing her to the ground and handcuffing her. The officers then tie her feet and leave her tethered to the cell door.

Normally the investigation would be carried out internally, but Ryneveld said that the Victoria police have defended their actions and compromised their impartiality.

Still, Victoria police have launched their own investigation interim Victoria Police Chief Bill Naughton told a news conference Wednesday, adding that he would go public with the results.  

"I have directed an immediate internal investigation into this event," Naughton told reporters. "However, it is important to recognize that this video being circulated is a snapshot of a much longer period of time in which she was in our custody."

Kinloch and her parents are suing the city of Victoria and four police officers for alleged assault and unlawful confinement of their daughter while in police custody in 2005.

The lawsuit, seeking $90,000 in damages, is based on the videotape, Kinloch's lawyer Richard Neary told CTV British Columbia.

Police say Kinloch, now 18 years old, was intoxicated and placed in a cell to sober up. They say they had to use force because the teenager was combative and uncooperative.

Police were first called to attend to Kinloch after a neighbour called in, saying she was concerned for the girl's safety.

"She was brought to our attention by a bystander who phoned and was frantic because she was concerned for this girl's safety," Victoria police spokesman Sgt. Grant Hamilton told CTV British Columbia. "She disclosed to that caller that she had been drinking and taking ecstasy."

Hamilton said police attended the scene after medical staff called for assistance.

Later, Hamilton says, police were unable to contact any members of her family. Not legally allowed to release her onto the street, police say they had no choice but to bring her back to the cell.