Venod Skantha (32) is on trial before the High Court at Dunedin charged with the murder of Amber-Rose Rush and four counts of threatening to kill.
The victim was found dead in the bedroom of her Corstorphine home on February 3 last year and the Crown says the doctor had a clear motive to cause her death.
Just minutes before Amber-Rose's death she had threatened to go to authorities with allegations of molestation against Skantha, along with further allegations that he offered teenage girls money for sex and supplied alcohol to minors.
A witness, whose name was suppressed because he was under 18 at the time, told the court yesterday he regularly socialised with the victim and the defendant through 2017 and early 2018.
He initially described Skantha's interest in his friend as ''creepy'' but under cross-examination amended that description.
He said the defendant was ''fascinated'' by both the victim and her mother Lisa-Ann.
A month before Amber-Rose died, a group of young people went to Skantha's Fairfield home to watch a movie.
The man went home, leaving the victim alone with others sleeping on the couch, and they met the next day.
''She told me she'd woken up with her bra off and Vinny's hand down her pants,'' the witness told the court.
Despite that, Amber-Rose went back to the defendant's house four days later.
''She told me Vinny offered her money in return for sex ... $2000 initially then it went up to $20,000 when she denied him,'' he said.
''She told me she ended up slapping him in the face, getting herself packed up and leaving as soon as possible.''
Defence Counsel Jonathan Eaton QC questioned why the man would have let Amber-Rose continue to associate with Skantha if the indecent assault allegations had actually occurred.
The witness said he trusted the victim.
''I don't believe she was lying to me. We didn't need to lie to each other, that's why we were such good friends,'' he said.
The teen also told the court about an occasion on which Skantha had brandished a machete he had stashed under a pillow at his house.
''[He] elaborated on how easy it would be to remove someone's head with it,'' the man said.
''I just dismissed it as nothing.''
Earlier, another teenage witness, whose name was also suppressed, gave evidence of financial incentives provided by the defendant in exchange for sex.
She spoke about being at a party with her boyfriend at Skantha's home in June 2017.
The next day, they were speaking about one of her schoolmates when the defendant allegedly chipped in.
''Vinny asked would she have sex with him for $400,'' she said.
''He asked me to ask her and I said that I wouldn't.''
The witness said Skantha repeated the offer about 10 times and she believed it was legitimate.
''You didn't think he was just being a drunken idiot?'' Mr Eaton asked.
''No,'' she said.
A week later, the teenager said, she got a phone call from the defendant.
First he asked her to dinner, then asked her to pass on the message to her friend then finally asked her if she would have sex with him for $400.
She refused all three requests.
Under cross-examination, the witness was adamant Skantha did not sound drunk at the time.
The trial, before Justice Gerald Nation and a jury of 10 men and two women, is likely to end next week.
