Willows and rocks fill the area around the Manuherikia River, to the east of Alexandra, near the railroad bridge. Photos: Pam Jones : Searching scientific, thorough endurance

Alexandra Detective Sergeant Derek Shaw, one of the senior police heading the inquiry. : Searching scientific, thorough endurance

Land Search and Rescue volunteers get ready to search around the Alexandra railroad bridge area last weekend for Christopher Bates. : Searching scientific, thorough endurance

Members of the Fiordland Search and Rescue team search near the Manuherikia River last month. Photo: Tom Kitchin : Searching scientific, thorough endurance

Central Otago Land Search and Rescue member and Alexandra search team leader Eric Schusser looks over some of the area being searched. : Searching scientific, thorough endurance