A "sinister and brutal" double killer who faces life in prison without parole took years to admit he raped his first victim and was never charged with any sexual offences, official documents show.

Paul Wilson, aka Paul Pounamu Tainui, who was a groomsman at David Bain's wedding, yesterday admitted raping and murdering 27-year-old life coach Nicole Marie Tuxford in the upmarket Christchurch suburb of Merivale last year.

It came 24 years after he killed Hokitika woman Kimberly Jean Schroder, 21, in near-identical circumstances.

Wilson, 56, was sentenced to 15 years' in jail without parole, reduced to 13 years on appeal, for the 1994 murder of Schroder.

After five appearances before the Parole Board – where Schroder's family and friends made vociferous objections to his lease - "model prisoner" Wilson was freed on parole on January 17, 2011 after being deemed a low risk of reoffending.

At his first hearing, in 2007, the board noted the sentencing judge's remarks that it was a "particularly nasty" murder, slashing her throat after "having sexual intercourse with her … and obviously fearing for her life".

During his trial, Wilson said it had been consensual sex. He was never charged with rape.

Even at his first Parole Board hearing, there were concerns that Wilson was still denying, and minimising, large parts of savage crime.

"His insistence that sexual intercourse with his victim was consensual is part of that," the board said.

Then in June 2008, Wilson seems to finally have admitted that he raped Schroder.

"What we have experienced today is Mr Wilson's ability with language. He now confirms, instead of talking about 'making love' to his victim, he says, 'I forced her' and he uses the word 'rape'," the Parole Board said.

And by December 2010, at a hearing that decided he was suitable for release from prison, the board wrote: "He accepts that he also raped [Schroder] although he was not charged with that offence."

When he was released in 2011, he was subject to special conditions for the first five years of his parole and standard conditions for life.

While he seemed to be making a good fist of life back in the community – with a tidy flat and solid work – it all ended catastrophically last year.

The High Court in Christchurch heard how Wilson and Tuxford had known each other for about a year before the murder.

They had socialised together in the same circles and Tuxford told her mother that she "felt sorry for him" and wanted to help him out with some life coaching.

But early last year, Wilson said he wanted a sexual relationship.

Tuxford's life coach suggested that she pull away and reduce contact with the man.

On March 24, she invited him over for a chat and a drink for a set period of 90 minutes.

Wilson told her he wanted to spend more time with her but she made it clear that it would only be for that timeframe.

Two days later, he sent her a text message saying that he'd found out she was in a relationship with another male and that he felt "p***** off" and lied to.

On April 6, Tuxford stayed at her partner's house across town.

Meanwhile, her killer spent the night drinking at his local bar.

At around 9pm, he drove to Tuxford's house. She did not reply to his text messages or pick up his calls.

On the way, Wilson was stopped by a police booze bus and failed a drink-drive test.

Police took his keys and he was issued a court summons.

Wilson got a taxi to Tuxford's house.

He lay in wait for eight hours overnight before she got home at around 7.40am.

As Tuxford entered her Exeter St home, the convicted killer pounced on her.

Her screams were heard by neighbours as he overpowered her and took her captive in a spare bedroom. He pulled the curtains and shut the door.

An electrician then turned up for a scheduled appointment and walked around the house trying to see if anyone was home.

Tuxford tried to fight him off and bite him, while he punched her in the face.

Trying to silence her and keep from raising the alarm with the electrician, who could hear muffled noises coming from inside the house, Wilson gagged her with the scarf.

He then strangled her, breaking her thyroid cartilage, before he cut her throat multiple times, "almost severing her head from her body", the court heard.

The killer took off in her car and wearing one of her hats.

He then had a medical event or seizure and crashed nearby. Unresponsive, he was taken to hospital.

Meanwhile, the electrician returned to the Exeter St house, worried about Tuxford.

He climbed in through a window and found her dead on the floor.

The electrician phoned police and they caught up with the man at Christchurch Hospital, where he admitted the killing.

The shocking news that Wilson had killed again was too much for Schroder's father.

Gary James Schroder, 67, died in a suspected suicide just hours after Wilson made his first court appearance on April 10 last year.

While Wilson earlier admitted murdering Tuxford, he had denied a charge of rape.

However, at the High Court yesterday, he pleaded guilty to rape.

He is remanded in custody for sentencing on March 28.