SAVAGE, Minn. (WCCO) — The Savage police officer that sustained head injuries in a car accident while responding to a call remains in critical condition.

Frank Mackall, 39, remains at North Memorial Medical Center Tuesday morning. Authorities say Mackall suffered critical head injuries in a single-vehicle accident on Monday, while he was responding to a call.

The cause of the accident is still under investigation by the Minnesota State Highway Patrol.

Mackall joined the Savage Police Department in July of 2008. He lives in Cottage Grove with his wife, Lisa, and their three children.