Police have appealed to the killer of a Waikato woman to show compassion and reveal the location of her body.
Mark Pakenham has admitted killing former girlfriend Sara Niethe by giving her methamphetamine in 2003.
The 50-year-old had been charged with her murder, but pleaded guilty to the lesser charge of manslaughter in the Hamilton High Court on Friday.
Sara Neithe was last seen on CCTV in a shop on her way to visit Pakenham in Kaihere in March 2003. Her body has never been found.
Detective Sergeant Glen Tinsley told Radio New Zealand's Checkpoint programme on Friday that so far, Pakenham is not cooperating and the focus is to bring Ms Niethe home.
"We just hope that he'll see reason and do the right thing by he family. Just show some compassion towards that family and not to back up what is viewed as a monstrous act with another evil act really."
Mr Tinsley said police have no reason to believe anyone else knows where the body is.
He said he has mixed feelings about Mark Packenham's plea on Friday. "Bittersweet, but a lot of work's gone into it and it's just one step further in the process of bringing it to a conclusion."
The details of what Pakenham says happened on the night Sara Niethe died remain suppressed, as a disputed facts hearing is taking place on 27 June.
Pakenham also pleaded guilty to assaulting two other women in Auckland in 1990 or 1991, and in 1992. He has been remanded in custody for sentencing on 28 June.