A High Court jury has found Venod Skantha guilty of the murder of Amber-Rose Rush.

Skantha's also been found guilty of four charges of threatening to kill in relation to the Crown's key witness in the case.

Amber-Rose's sister, brother and step-father were in the courtroom when the jury of 10 men and 2 women delivered their verdict.

The Dunedin doctor's trial drew to a close today after three-and-a-half weeks.

The jury heard statements from 69 witnesses. They had more than a thousand pages of evidence and numerous exhibits to consider. They deliberated for close to three hours after the judge summed up this afternoon.

The judge said whoever killed Amber-Rose Rush intended to do so. Photo / Facebook

Skantha pleaded not guilty to murdering 16-year-old Amber-Rose Rush — who was found in bed with her throat slashed at her Corstorphine home by horrified family members on February 3 last year.

He also pleaded not guilty to four charges of threatening to kill — relating to the Crown's star witness in the case against him.

Before the jury was released, Justice Gerald Nation warned them to be careful of sympathy and prejudice.

"You could have strong sympathy for Amber-Rose Rush, her family and her friends… for young witnesses called before the court … and even for Dr Skantha, a young man who's found himself in this predicament.

"You may also have had prejudice… against young people behaving in a way alien to you, against Dr Skantha for hanging out with young people, or even the young people for how they used him and his home."

Nation urged them to look past those feelings — and to consider any ways they might be prejudiced.

The judge told the jury they had to decide whether the Crown had proven beyond reasonable doubt Venod Skantha was the person who killed Amber-Rose. Photo / ODT

"Fundamental to a fair trial is the presumption of innocence. Dr Skantha was under no obligation to give evidence in this trial. [You should also discount] reports in the media — particularly headlines which can be sensationalist, and the fact bail was denied to Dr Skantha."

Nation says the jury had to decide whether the Crown had proven beyond reasonable doubt Skantha was the person who killed Amber-Rose.

"Beyond reasonable doubt is a very high standard of proof. A reasonable doubt is not going to be based on a fanciful possibility."

He also noted the defence's main argument — that the Crown's star witness was the real killer.

"If you decide [the teen witness] could've been an accomplice… it does not mean you have to find Dr Skantha not guilty."

Nation also addressed arguments used by the defence about the demeanour of the witness — and of the accused — both in court and in police interviews.

"Demeanour may not be a good indicator of truthfulness — and people can lie for different reasons. It may not mean they're guilty.

"You cannot infer from the fact [the star witness] lied in past police interviews about a sexual assault charge he was facing that he was lying this time… You cannot infer the fact that Dr Skantha lied about his mother dying to avoid losing his job that he's guilty of this crime."

Nation said one thing, however, was clear.

"When Amber-Rose Rush was lying in her bed, someone cut her neck. Whoever cut her neck must have intended to kill her. The real question is whether you're satisfied that person was Dr Skantha."

Yesterday Crown and defence lawyers summed up their cases for and against Skantha — with the defence arguing the crown's star witness is the real killer.

Lawyer Jonathan Eaton, QC, said the teen had a documented record of lying to police when he was interviewed about a past sexual assault charge — and one only has to watch his police interviews for this case to see how he could be implicated.

"He's living in a different world to us — it's a fantasy world. In the interviews he's constantly making movie and music references, like Little Feat's You can get further if you commit murder.

"He's put himself in the middle of a script where he's the star."

Eaton said the teen was constantly checking his hair in the interview videos, and reclined in his seat.

He said it's unlikely someone who'd just gone through the most traumatic experience of their lives could be that calm.

"During cross-examination, he says he can't remember 161 times. He asks 'can you repeat that?' 26 times, and asks if he can have a moment 18 times. He doesn't do that once in the interviews."

Eaton compared his behaviour to when Skantha was first picked up and interviewed by police on the 4th of February, 2018.

"[Skantha] doesn't even ask for a lawyer. You witnessed first-hand how he responded to a very forceful interview," he told the jury.

"You saw someone very calm, truthfully answering questions."

"When it became accusatory, he was hurt, offended and shocked by the allegation he'd killed Amber.

"What he doesn't do is turn on [the key witness]. He doesn't make all sorts of allegations against [key witness]."

The judge said whoever killed Amber-Rose Rush intended to do so. Photo / Facebook

Eaton said the jury couldn't find Skantha guilty if they had any doubts about the Crown's young key witness — a self-professed compulsive liar.

"We haven't heard the truth, the whole truth and nothing but the truth from the key witness."

Eaton told the court the teen was never even considered as a suspect by police — tarnishing the whole investigation.

"Venod Skantha did not kill Amber-Rose Rush — he has been falsely implicated."

Crown lawyer Robin Bates rubbished the defence's argument in his closing statement.

He said the boy would've had to be a criminal mastermind.

"Is [the teen witness] a magician who could pull a knife out of nowhere?"

He also noted all location data and messages from Skantha's phone had been deleted for February 2 and 3 — while the teens were still there.

"He's not a compulsive liar — he exaggerates and makes unusual comments from time to time. He's not a person who would kill — and he's not a person who would set up his friend for murder."

Bates urged the men and women of the jury to use their common sense.

"It was Dr Skantha that killed Amber Rush. The appropriate verdict is the verdict of guilty."