A doctor who killed Dunedin teen Amber-Rose Rush has been jailed for at least 19 years.

Venod Skantha was found guilty of murdering the 16-year-old, who suffered multiple stab wounds to the back of her neck, after a jury trial late last year.

The 32-year-old, who was also found guilty of four charges of threatening to kill relating to a star witness and his family, was sentenced to life imprisonment with a 19-year non-parole period by Justice Gerald Nation in the High Court at Dunedin on Friday.

HAMISH MCNEILLY/STUFF Dunedin doctor Venod Skantha has been sentenced to a minimum of 19 years prison.

Skantha, who had a thick black beard and a short haircut, wore orange earplugs as he entered the dock before a packed public gallery.

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His counsel, Jonathan Eaton QC, said his client was conscious of the grief suffered by the Rush family, and steadfastly maintained his innocence.

SUPPLIED Amber-Rose Rush, 16, was found dead in her Dunedin home in February 2018.

He told the court that Skantha did not want his own family to support him in court, or to write a letter of support.

He indicated an appeal on the basis of a miscarriage of justice was likely.

'BEST FRIEND' LOST

SUPPLIED Lisa Rush and her daughter Amber-Rose Rush.

Amber-Rose's brother, Jayden Rush, read a victim impact statement from his late mother Lisa-Ann, who died of a suspected suicide in the months after the killing.

She had lost her "best friend", and she was the person who brought their family together but her death had pulled them apart.

"I am completely broken ... completely empty."

JOHN KIRK-ANDERSON/STUFF The Dunedin house where Amber-Rose was killed.

She wished she could be with Amber, and suffered nightmares. She was fearful of the outcome of the court case.

All she had was a box of ashes to remember her daughter.

Other members of the family were not in a position to read their statements, but Justice Nation assured them he read them all.

He hoped that writing those statements would help, but acknowledged the grief may never leave them.

But those statement helped remind Skantha of the "terrible consequences" of the death of Amber-Rose.

He could not make-up for the loss of Amber-Rose, but he could sentence Skantha for his crime.

Justice Nation noted that in the months before the murder Skantha's life went "off the rails", including drinking heavily, and his predatory behaviour towards young women.

Skantha's behaviour - and crime - were "irrational and illogical".

He questioned why a person with the discipline and intelligence to become a doctor, would kill a young woman "in the way you did".

FATAL FINAL WARNING

The Crown said Skantha, who was at the time on his final warning with his employer, feared Amber-Rose was about to raise accusation that would destroy his faltering medical career.

Those accusations, made on the night of Friday, February 2, 2018, included him offering her money for sex.

The post alleged Skantha would turn up to work drunk, supply alcohol to minors and touch them inappropriately.

"Grow up Vinny, You're 30 for f... sakes," it said.

Another text conversation was sparked between the pair when Amber-Rose threatened to go to the police "like I should have in the first place".

She messaged him about "supplying minors with alcohol and offering them money for sex", and later added she would tell his work and police.

Skantha messaged her at 11.21pm: "So ur serious?"

"Best believe I am," she replied.

The terse exchange ended at 11.25pm with Amber-Rose telling Skantha: "I hope you pay for it and I hope you go to sleep at night hating yourself."

Skantha was made aware of those social media posts by the teen star witness, who he got to accompany him to Amber-Rose's Clermiston Ave house to carry out his "masterplan".

​Parked around the corner as the teen waited in the car, the gloved Skantha used a spare key to get into the house and then entered her bedroom.

NO SIGNS OF STRUGGLE

Amber-Rose, who died face down with four pillows stacked behind her head, showed no signs of struggle.

She would have bled out within minutes from the 11 centimetre-long fatal would, which severed part of her ear and reached to the base of her skull, an ESR scientist told the jury.

Justice Nation noted that on the night of the murder Skantha was able to kill Amber Rose without waking her mother or her partner.

He noted the callousness of how she was murdered, and how her bloodied body was left for her mother to discover.

Skantha later disposed of the cellphone, before returning to his Fairfield home to clean-up the vehicle.

The doctor and the teen then went to Balclutha, at the home of his former partner, where he burnt the clothing he wore during the killing.

He later told the teen what he did.

The trio then returned to Dunedin, and met with the victim's mother, and unbeknownst to them an undercover cop.

Outside side court Amber-Rose's father, Shane Rush, thanked the judge, prosecution and "everybody".

"The life sentence is not what we would have asked for - we would have asked for more, but it is what it is.

"From all of us we'd like to thank the country...myself and my children will just go on and be strong together."

Detective Senior Sergeant Rob Hanna said the aim was always "to do the best for the family".

"Two years down the track and we still feel for the family and their loss."

The case was heard over nearly four weeks and involved more than 1000 pages of evidence and dozens of witnesses.