Two days after allegedly stabbing a teenage girl to death, a Dunedin doctor met the victim's mum and gave her flowers and a card.

Venod Skantha, 32, bought the items, his ex-girlfriend Brigid Clinton told the High Court at Dunedin today, from New World – where the victim 16-year-old Amber-Rose Rush had worked.

Skantha has pleaded not guilty to murder and also denies four counts of threatening to kill.

The doctor is accused of being driven to the scene by a teenage friend and inflicting six wounds as the girl lay in the bed at her Corstorphine home late on February 2 last year.

After spending a couple of nights at Clinton's Balclutha home, during which the Crown said Skantha burned the bloodied clothes he wore to commit the murder, they went back to his Dunedin house.

While there, she said the defendant's 16-year-old friend got a call from Amber-Rose's mother Lisa Anne Rush.

She wanted to speak to anyone who had had contact with her daughter.

A decision was made, Clinton said, to visit Lisa Anne Rush in the hotel at which she was staying and the items were purchased on the way.

Skantha also bought a couple of bottles of wine for himself.

"Lisa was obviously really upset . . . pale, in shock," Clinton told the court.

"I remember Venod was sat next to her and suggested it was a suicide to which she vehemently said no."

There was then a discussion about potential suspects, she said, before they left.

At home, Clinton said her ex-partner seemed in "irritated, almost indignant" mood and was receiving numerous alerts on his phone.

He asked her to retrieve his samurai sword.

While "waving it around above himself", Skantha cut his finger and Clinton took him to the urgent doctor to be stitched up.

On their way home, police pulled them over and they were taken for interview.

"I was in shock," she said, after being told of the allegations.

The Crown case is that Skantha killed Amber-Rose because he was concerned she would follow through on threats to make sexual allegations to police and his hospital bosses.

It would have effectively ended his medical career, prosecutor Richard Smith said.

Accused toasted marshmallows while burning evidence: Witness

After committing the alleged murder, the Crown said Skantha was driven home by his mate and then south to Clinton's.

She told the court this morning their relationship of more than a year had ended a couple of months before the night of Amber-Rose's death but she was expecting Skantha to visit her that evening to sign some legal documents.

At about 1am, approximately an hour after the alleged murder, she received a message from her ex-boyfriend saying he had been asleep and was now coming over.

Clinton told him not to.

She was "done with him, done with it", she said.

An hour later, however, Skantha arrived at the house along with his 16-year-old associate.

They all went to bed and the next day visited The Warehouse.

"Venod mentioned having a bonfire; something to do," Clinton said.

They couldn't find a coal bucket but purchased a large terracotta pot instead.

Shortly after getting home, Clinton went back to the store to return one of the items they had bought and came home to find the fire ablaze in the yard of the property.

"Venod said he was burning his daggiest clothes," she told the court.

They consisted of a charcoal grey jumper he wore around the house and a pair of light grey sweat pants, he told her.

Clinton said she sat and talked with Skantha while they toasted marshmallows over the flames.

The ashes were later tossed into the garden, the witness said.

In cross-examination by defence counsel Jonathan Eaton QC, the woman said her ex-boyfriend had a growing alcohol problem.

Clinton said Skantha was drinking sauvignon blanc "pretty much non-stop" by the end of their relationship, swigging from the bottle.

"He took steps to try and sort himself out but it just didn't last," she said.

After lunch, the jury is being taken to view the scene where Amber-Rose died before evidence continues this afternoon.