An outside police force has been called in to investigate after a 15-year-old girl's arm was broken during an arrest by B.C. Mounties.

RCMP officers were called to a home in Prince Rupert because of a domestic dispute between the girl and her mother on April 4. When police arrived at the house, they say they learned the teen was so upset she wanted to commit suicide.

The Mounties tried to arrest the girl under the Mental Health Act, but she allegedly assaulted one of the officers. Police say her arm was broken during the struggle, but the officer was unharmed.

The Delta Police Department is now investigating to determine if any wrongdoing was committed during the arrest.