KEY POINTS:
The murder of 77-year-old Doreen Reed was so brutal it attracted the attention of the FBI.
When Supervisory Special Agent Mark Safarik - a behavioural analysis expert at the FBI academy in Quantico, Virginia - picked up the story, he made contact with Auckland police with an offer to help catch the killer.
A 15-year-old Glenfield boy is in custody, awaiting High Court sentencing, after admitting the killing in the North Shore District Youth Court on Wednesday. He cannot be named for legal reasons.
According to a police summary of facts released to the Weekend Herald, the teen had a row with his girlfriend in the early hours of January 13.
He left the girl's Birkdale home on his pushbike and went to Mrs Reed's home in Eskdale Road. He broke through two locked doors to the living area, and took a knife from a kitchen drawer.
After searching two bedrooms, he found the elderly widow asleep.
The 77-year-old pensioner was stabbed about 25 times in the subsequent attack.
The knife pierced her heart and skull. A number of wounds to her arms and hands showed she had attempted to fight off her attacker. After the killing, the boy turned Mrs Reed's Life Link medical alarm system off at the wall, cleaned off the knife and hid it behind the stove.
He then stole $50 and a set of car keys from Mrs Reed's handbag, and fled in her Rover car.
The power was turned on again, and the garage door shut as the boy left, police say.
He crashed the car into a curb on Verbena Rd, damaging a back wheel in the process, and had to stop at a nearby service station to make repairs.
The teen then returned to his girlfriend's house to pick up his bike. He stayed there the night. The man who led the inquiry into Mrs Reed's killing - Detective Inspector Steve Wood - said especially brutal attacks were not uncommon when young people attacked the old.
"There's international research showing that often the younger the attacker, and the older the victim is, the more brutal the attacks can be."
In the end, the services of the FBI were not required. Auckland police have criminal profiling of their own.
The teen - who was arrested about three days after the attack - gave no explanations for his actions and said her did not know Mrs Reed, police said.
