'Grave concerns' for Christopher Bates in week 4 of search

Police say the search for missing Alexandra man, Christopher Bates, is being treated as a missing persons case, but they are keeping an open mind about the circumstances of his disapperance. Twenty-two-year-old Christopher Bates hasn't been seen since February 11 when he left a service station in Alexandra. This weekend a group of 40 Search and Rescue volunteers and police carried out searches east of Alexandra, a helicopter explored areas more difficult to reach, and commercial boats looked along the Clutha River. Detective Sergeant Derek Shaw tells Susie Ferguson they have grave concerns as they enter week four of the search.