A bill requiring Virginia police departments to create a written policy on body cameras before the department can purchase or deploy a body-camera system has been signed by Gov. Ralph Northam.

“Body-worn cameras provide important evidence and context, especially when the facts of an interaction between an officer and a member of the public are in dispute,” Northam said Wednesday in a news release announcing a number of bill signings. “Model policies will help ensure public input across the Commonwealth and will increase needed transparency in our criminal justice process.”