Amber-Rose Rush's sister sounded warnings about her friendship with her accused killer in the months before she died.
The trial of former doctor Venod Skantha, who is accused of murdering the 16-year-old, today entered its second day in the High Court at Dunedin.
The crown claims Mr Skantha stabbed the teenager to silence her, after she told the 32-year-old she was going to the police and his employer, Southern DHB, with allegations of him "touching up" minors, supplying them with alcohol and offering money for sex.
The day began with evidence from Miss Rush's older brother, Jayden.
Mr Rush said when he arrived home soon after midnight on 3 February last year he found a spare key still in the front door.
It was not the only peculiarity he raised with his girlfriend when they got home that night after finishing work.
"When you got home you noticed the kitchen light was on. It was something you particularly noticed when got home and discussed with [girlfriend] Alicia?" defence lawyer Jonathan Eaton QC questioned.
"Yeah," Mr Rush responded.
He said his mother was "OCD about lights" and the lights would always be switched off before she went to bed.
Mr Rush knocked on his sister's bedroom door to mockingly tell her off for leaving the key in the door, but received no response.
Outside the home, Ms Rush's boyfriend, Kristin Clark, watched Mr Rush and his girlfriend enter the home.
Mr Clark had earlier been messaging Ms Rush on Snapchat.
"She was messaging me right up until the point she stopped replying and she was having a conversation with Venod and she seemed frustrated with him and was acting as if she was going to go around to his place to deal with the situation," Mr Clark told the court.
He advised his girlfriend not to confront Mr Skantha.
"When she stopped replying I drove around to her address to see whether or not her car was still there, because I was obviously worried whether or not she had gone to try and see Venod.
"I went to her window and knocked on the window and when she wasn't coming I knocked harder. But she still didn't come."
He went back to his car and when he saw Jayden Rush go into the house, he left.
Ms Rush was discovered dead in her bed by her mother on the morning of 3 February.
She had suffered stab wounds to her neck and throat, and there had been an attempt to slash her throat.
The crown alleged Mr Skantha entered the home shortly before midnight and killed Ms Rush, taking her cellphone to dispose of the incriminating conversations between the two.
Detective Constable Jesse Thomson said officers were unable to find the cellphone during a search of the property.
"I placed a phone call through to the officer in charge of the case, Detective Sergeant Robert Hanna, I advised him we had not been able to locate either a weapon used or the deceased's cellphone at this time.
"I asked him to consider ringing the deceased's cellphone so we could locate it within the address if it was present. A short time later he advised me that the phone had gone straight to answer phone."
Police suspected Mr Skantha had disposed of it in a swamp near Blackhead Quarry just outside of Dunedin.
Officers assisted by Fire and Emergency drained the swamp and using a metal detector, located a cellphone among weed and silt.
The court also heard how Miss Rush had planned to move into Mr Skantha's home with her best friend.
During the cross examination of her sister, Shantelle Rush, Mr Eaton covered a message exchange between the sisters in December 2017 detailing Shantelle's discomfort at the plan.
"You asked how old he is and she told you he was 30?" Mr Eaton asked Shantelle Rush.
"Yes," she responded.
"She told you he was lonely and like a dad to us.
"She told you he only hangs out with teens and you said sugar daddy?" Mr Eaton queried.
"Yes," Shantelle Rush replied.
"She told you he even said she could live rent free for cooking and cleaning?"
"But obviously it still wasn't persuading you because you said WTF, that's creepy as. And then you said it was sexual grooming."
The teenager dismissed her sister's concerns.
The crown claimed the friendship between Ms Rush and Mr Skantha soured after he offered her up to $20,000 for sex.
The defence said it accepted Ms Rush was stabbed to death by an intruder, but it did not accept that intruder was Venod Skantha.
The trial, held before Justice Gerald Nation, is expected to last about a month.