Nelson pleaded guilty in the High Court at New Plymouth yesterday to the murder of his caregiver, 50-year-old Rosemaree Kurth earlier this year.

Nelson was 13 years and 89 days old when he shot Ms Kurth in the back of the head with a .22 calibre rifle.

The nearest thing to a motive that the Crown could offer to the court was the fact that Ms Kurth had taken his Freeview TV receiver from him.

The boy also admitted to police that sometimes "she would get shitty with me".

Taranaki Daily News research has been unable to uncover a younger murderer since a law change in 1977 allowed children over 10 to be charged with murder or manslaughter.

In 1991, another 13-year-old murdered 23-year-old nurse Rachel Bennett after entering her Wellington flat and stabbing her 15 times.

Nelson appeared before Justice Timothy Brewer in the High Court at New Plymouth charged with Ms Kurth's murder.

Ms Kurth, who had three children and three grandchildren, was found dead at a rural house on Piko Road, Okoki, on April 15, with a gunshot wound to her head.

Nelson had initially denied the charge and was due to stand trial later this month, but yesterday changed his plea.

Justice Brewer lifted name suppression for Nelson and Ms Kurth, which had been in place since the shooting.

Ms Kurth's family and Nelson's family were seated in the public gallery for his appearance.

Nelson, who was wearing black trousers and a collared shirt, stood with his head bowed for most of his appearance.

Crown solicitor Cherie Clarke said Nelson thought of Kerry Lock, who was in a relationship with Ms Kurth, as his grandfather and the three had lived at the address since September 2010.

Mr Lock had known Nelson since he was a baby.

Nelson's father lives in Stratford and his mother lives in Napier.

Miss Clarke said about a week before her murder, Nelson was annoyed when Ms Kurth had removed the Freeview box from his room.

Nelson seemed to enjoy the rural life and Mr Lock had taken him hunting and fishing and taught him to use a .22 calibre rifle which was kept at the property, she said.

On the morning of April 15, Nelson got the gun out of the closet and the ammunition from the drawers and placed them in the sleepout, while Mr Lock was out walking the dogs.

Miss Clarke said when Mr Lock again left the house about 3pm Nelson took the gun from the sleepout and shot Ms Kurth once in the back of the head while she worked on a jigsaw puzzle at the dining room table.

Nelson then dragged Ms Kurth into her bedroom.

After ransacking Mr Lock's room and taking $16.10 in coins and a tusk carved necklace Nelson drove off towards Urenui in Ms Kurth's white Ford Telstar.

Mr Lock said he saw the car leaving and believed it was Ms Kurth going to Urenui for some reason.

When he arrived home Mr Lock saw a trail of blood leading from the dining room table to Ms Kurth's bedroom and the rifle on the floor about two metres from the table.

"The bedroom door was semi-closed. He opened the door and found Ms Kurth lying on her back," Miss Clarke said.

Mr Lock immediately presumed Nelson was responsible and informed emergency services.

Police later found Nelson driving along Bayly St in Waitara and he was arrested.

When interviewed by police the next day with his lawyer Patrick Mooney present, Nelson claimed to have a memory blank.

"He maintained he was going to the police in Waitara because he felt like he had done something wrong but didn't know what it was," Miss Clarke said.

Nelson told police his relationship with Mr Lock was good and he had done a lot for him.

However, when asked about how he got on with Ms Kurth Nelson said "sometimes not that good".

"If I do something wrong she gets shitty with me," he said.

He gave examples of being grounded for a month, stopped from visiting his mother in the school holidays and not getting his $20 for mowing the lawns.

Nelson later admitted to police Ms Kurth had died because he had shot her, Miss Clarke said.

Justice Brewer convicted Nelson and recorded a first strike warning against him.

He remanded Nelson in custody until December 20 for sentencing and ordered that a pre-sentence report and victim impact statements be prepared.

"What is going to happen to you is going to be determined at your sentencing," Justice Brewer said.

NEW ZEALAND'S YOUNGEST KILLERS

1991: A 13-year-old Wellington schoolboy was convicted of the murder of nurse Rachel Bennett, who was stabbed 16 times. He has permanent name suppression.

1994: Anthony Alfred Afu, 14, beat John Wahanui to death with a piece of wood in Auckland. Originally charged with murder, he was eventually convicted of manslaughter.

2001: Bailey Junior Kurariki, was just 12 when he was involved in the killing of pizza delivery man Michael Choy in 2001. He was convicted of manslaughter.

2003: Renee Kara O'Brien was convicted of the murder of Waitara truck driver Kenneth Pigott. O'Brien was 14. Her co-offenders - Puti Irene Heather Maxwell and Kararina Makere Te Tauna, both 14 - were convicted of manslaughter.

2008: Kalem Ames, 14, stabbed Tokoroa man Shayne Pita Walker, 22, to death in the town. He was charged with murder, and a jury found him guilty of manslaughter.

2008: Jahche Broughton, 14, bashed 27-year-old Scottish tourist Karen Aim to death in Taupo. He was sentenced to life imprisonment for Ms Aim's murder.

2008: Teenage cousins Courtney Patricia Churchwood, 16, and Loi-lea Waiora Te Wini, 14, murdered retired Opotiki school teacher John Rowe.

2009: A 12-year-old East Coast boy shot an 11-year-old boy dead and pleaded guilty to manslaughter.

Fairfax NZ News