Who Killed Kirsty Bentley? Investigation into the murder of Ashburton teenager Kirsty Bentley questions why police allow her father and brother to remain under a cloud of suspicion. Bentley disappeared on New Year’s Eve 1998. Her body was found several weeks later covered by branches in the Rakaia Gorge. The Christchurch officer in charge of the Bentley case, Detective Inspector Greg Williams, declined to have anything to do with the show. The Investigator is a New Zealand unsolved murder series presented by award winning documentary maker and author Bryan Bruce.