Stephanie Scott's killer faces sentencing
School cleaner Vincent Stanford told police he "went a little nuts" when he felt an irresistible urge to kill teacher Stephanie Scott six days before her wedding.
"I agree to the charges and confess to the murder of Stephanie - I can't remember her surname," the 25-year-old told detectives at the start of a chilling videotaped interview at Junee Correctional Centre on April 11, 2015.
Asked why he murdered Ms Scott, Stanford responded: "I think I went a little nuts. I just could not stop myself."
Stanford dragged her into a store room at Leeton High School and punched her up to 40 times until she stopped moving, then stabbed her in the "carotid artery" with a 40cm knife "to make sure she was dead".
He said a feeling came over him "just that I had to kill her".
"I wasn't angry or anything. Basically emotionless," Stanford told detectives.
He said he cleaned Ms Scott's blood with a high pressure cleaner and later drove her body to the Cocoparra National Park, 70 kilometres away, and burned it.
The disturbing video was played at the killer's sentence hearing in Griffith, southern NSW, on Tuesday.
Crown prosecutor Lee Carr cited an expert medical report that said Stanford revealed thoughts of killing people since the age of seven or eight.
According to the report, Stanford has autism and once said he couldn't adapt to society because he would have to acquire emotions, of which he had almost none - except hatred.
Stanford pleaded guilty in July to the aggravated sexual assault and murder of Ms Scott at Leeton High on Easter Sunday April 5, 2015.
In the interview Stanford calmly told police he laid in wait and grabbed the unsuspecting 26-year-old as she was leaving the school that day.
She had come in on the Easter Sunday to prepare lessons for a substitute teacher before going on leave for her wedding and Tahiti honeymoon.
According to an agreed statement of facts the cleaner had regularly searched for violent rape, hard-core porn and murder online and had ordered handcuffs and a "half-sword" through a security company.
Soon after he began working at Leeton High School he made a number of internet searches related to brides, including "bride rape" and "bride kidnapping", according to the facts.
During the hearing Stanford sat in the dock with his head turned away from the public gallery where Ms Scott's family was seated metres away.
Heartbroken mother Merrilyn Scott said her loving daughter would have been at a loss to comprehend how the "despicable", "pathetic" and "inept" Stanford could betray her.
"We will never know what she suffered, but to know that she suffered at all is difficult for us to bear," Ms Scott read in a shaking voice from a victim impact statement with husband Rob by her side.
Mr Carr asked for Stanford to be locked up for life.
"This was a cold blooded merciless sexually motivated killing," Mr Carr said.
But Stanford's barrister Janet Manuell urged Justice Robert Hulme to take into account mitigating factors including his autism and guilty plea.
She asked the judge to impose a "very long determinative sentence".
Justice Hulme is due to sentence Stanford on Thursday.