Ms Millane was strangled, stuffed in a suitcase and buried in the bush after going on a Tinder date with the defendant, 27, who cannot be named for legal reasons.
He told the jury she had died accidentally during “rough sex”, but prosecutors said the man killed the backpacker deliberately to fulfil a “morbid sexual interest”, taking seven “trophy” photographs of her body and then going on a second date with another woman before he had disposed of Ms Millane’s body.
The defendant showed no emotion as the jury unanimously found him guilty after five hours of deliberations.
Ms Millane, from Wickford in Essex, had been travelling through New Zealand as part of a planned year-long round-the-world trip after graduating from the University of Lincoln.
Ms Millane’s parents, who have been present in the public gallery throughout the trial, wept as the verdict was read out. Speaking outside the courtroom, her father David Millane said Grace “did not deserve to be murdered in such a barbaric way during her gap year”.
Alongside his wife Gillian, Mr Millane said: “The verdict of murder today will be welcomed by every member of the Millane family and friends of Grace. It will not reduce the pain and suffering we have had to endure over the past year.
“Grace was taken in the most brutal fashion a year ago and our lives have been ripped apart. Grace was our sunshine and she will be missed forever.”
Justice Simon Moore referred the case for sentencing on 21 February. The man is expected to face a mandatory life sentence, under which he will not be eligible for parole for a minimum of 10 years.
Ms Millane died on either 1 or 2 December 2018 – the latter being the date of her 22nd birthday. After she was reported missing, Mr Millane flew to New Zealand and joined local authorities in a week-long search effort before her body was eventually found.
In his closing statement, crown prosecutor Brian Dickey told the jury at Auckland High Court that after Ms Millane’s death, the defendant watched pornography, arranged another Tinder date and searched the internet for the Waitakere Ranges, where the 21-year-old’s body was later found.
Mr Dickey told the murder trial that the defendant was “seeking total domination and some sort of weird thrill over women who were his sexual partners”.
Addressing jurors before they delivered their verdict, Justice Moore said they had to be certain the man had murderous intent when he put his hands on Ms Millane’s neck during sexual intercourse to convict him of murder, The New Zealand Herald reported.
Mr Moore asked: “Are you sure that when he applied pressure to Ms Millane’s neck... Did he intend to cause injury?”
He further asked them to consider if the accused was willing to take the chance of Ms Millane dying due to his actions. “If yes, then [the defendant] is guilty of murder,” the judge said.
“In other words, [he] must have appreciated Ms Millane’s death was a likely consequence... but was willing to run that risk.”
The court had been told Ms Millane had an interest in BDSM, with a previous sexual partner testifying they had used safe words and physical tapping to indicate when physical pressure became overwhelming.
During the trial, the jurors heard from forensic experts who examined the accused’s apartment for blood stains as well as Ms Millane’s body after her death.
They were also shown footage of Ms Millane and the defendant drinking at various bars throughout Auckland and kissing before they returned to his apartment.
Video footage from the lift of her exiting on the third floor marked the last recorded time Ms Millane was seen alive.
The confirmation of Ms Millane’s death was met with shock in New Zealand, a country with one of the lowest murder rates in the world.
After the defendant first appeared in court, New Zealand’s prime minister Jacinda Ardern issued an emotional public apology to the Millane family. “Your daughter should have been safe here, and she wasn’t,” she said. “And I’m sorry for that.”
Additional reporting by agencies
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