During his confession to police Vincent Stanford said "I think I went a little nuts" when he murdered school teacher Stephanie Scott on Easter Sunday last year.

"I think I needed to see a psychiatrist but I didn't," Stanford told police during a recorded police interview that was played in a NSW Supreme Court sitting at Griffith on Tuesday.

When asked by police what he did on the day of the murder, Stanford spoke clearly and without hesitation.

"I did it at the high school...I beat her to death."

The 25-year-old said he struck Ms Scott 30 or 40 times and offered no explanation as to why he killed her.

"I don't know, I just felt like I should do it," he said. "Just that I had to kill her."

Stanford also confessed to having tried to strangle a teacher when he was 13-years-old and was put in a mental institution for two months.

On Easter Sunday last year Ms Scott went to Leeton High School to prepare lessons for a relief teacher who was to take her place while she went on her honeymoon.

The 26-year-old English and drama teacher was just days away from marrying her partner of five years Aaron Leeson-Woolley when she was attacked by Stanford on school grounds, and later raped and killed.

Stanford told police during the interview that he had discarded Ms Scott's clothes in various garbage bins around Leeton.

Then, after he had put her body in the boot of her own car, he used a high pressure cleaning system to clean the blood left behind in the storeroom where he killed Ms Scott.

Stanford's police interview was played to the court just moments after Ms Scott's mother Merrilyn Scott read a victim impact statement to the court, with her husband Bob at her side.

She told the court each night she said "goodnight my darling girl" from the darkness of her bed.

"Nights are haunted by visions so terrible it is difficult to find rest," she said.

Ms Scott's voice wobbled as she asked: "Did she see the knife ? Did she see the fist before he pounded her precious life into oblivion?" 

She told the court Stanford had access to six schools at the time he raped and killed her daughter at Leeton High School.

"There were many behaviours that should have raised red flags," she said.

Stanford was seen for the first time in public since the April 2015 murder when he was walked into the Griffith courthouse by Corrective Services officers on Tuesday morning . 

Members of Ms Scott's family and Mr Leeson-Woolley arrived at the court on Tuesday morning dressed in yellow, her favourite colour.

It was Ms Scott's family who frantically searched and fretted when Ms Scott disappeared while Stanford worked furiously to cover up his crime.

After Stanford placed Ms Scott's body in her red Mazda 3 he drove it to his house in Maiden Avenue at Leeton.

Court documents outline how he later drove Ms Scott's car, with her naked body still inside, to Cocoparra National Park, about 70 kilometres north-east of Leeton, near Griffith.

He doused her body in petrol before setting it alight and in a depraved act he took photographs of her remains.

In July Stanford pleaded guilty to the aggravated sexual assault and murder of Ms Scott.

And in an act that sickened Ms Scott's family to their core, Stanford sent the young teacher's engagement and graduation rings to his twin brother Marcus in South Australia.

In August Marcus Stanford was sentenced to one year and three months in jail after he had earlier pleaded guilty to being an accessory after the fact to murder.