Nikki Roper has been found guilty of murdering his ex-girlfriend Alexsis Tovizi in a jealous, revenge-driven rage.
A jury took four hours today to agree he killed the mum-of-one with a sleeper hold at her Christchurch flat in 2010, just five days after being released from prison where he was serving a sentence for choking her.
As Justice Miller was telling Roper that he will be convicted for murder, Roper shouted out to Ms Tovizi's mother, Cheryl Tovizi, in the public gallery: "F*** up b***''.
He then charged out of the dock and attempted to attack another person in the gallery.
Court security staff tackled him as he struggled violently with them, and he was thrown back into the cells.
He could be heard screaming as security tried to contain him and calm him down.
After a short adjournment, he was brought back into the dock where Justice Miller completed giving Roper his first strike warning, and telling him he would be sentenced on July 3.
As he was taken into custody, Roper turned to the gallery again and said: "Just remember what happens when you nark on the Mongrel Mob eh.''
Anthony Bougham, Ms Tovizi's father, welcomed the guilty verdict.
Speaking on Mr Bougham's behalf, Dunedin Police area commander, Inspector Greg Sparrow, said: "Anthony's family feels a real sense of relief at the guilty verdict that the jury has delivered in this trial.
"We now hope that the appropriate sentence will be imposed reflecting the devastating impact that this murder has had on Alexsis' family ...
"The past two and a half years has been an extremely trying time for the family. We now turn towards the future but always remembering Alexsis as a bright caring and funny young woman and mother.''
As he left jail in 2010, Roper told an inmate: "I'm going to kill the b****".
The family wept and clapped as the jury of eight women and four men read out their unanimous verdict.
"Thank God," said her mother, Cheryl Tovizi.
Roper, a 24-year-old unemployed Christchurch man with 'Alexsis' tattooed under his left eye, was also found guilty of unlawfully taking her car, stealing her laptop, and five charges of dishonestly using her bankcard.
He had denied strangling the student social worker, before possibly drowning her on the night of December 4, 2010.
Ms Tovizi had earlier taken a protection order out against him, but her mother Cheryl Tovizi said Alexsis stayed in touch with him.
The seven day trial at the High Court in Christchurch heard "overwhelming" evidence Roper killed Ms Tovizi, according to the Crown earlier today in closing submissions.
Roper's defence claimed she died of natural causes related to binge drinking.
While she died of pulmonary oedema, or fluid in the lungs, three pathologists couldn't be sure what caused it.
Earlier, the Crown told how Roper was "obsessed" with his on-again-off-again girlfriend.
And when he was released from a prison on December 1, he allegedly told an inmate he was going to kill his girlfriend because she had cheated on him.
"Five days later, she was dead," said Crown prosecutor Pip Currie, adding it was a killing fuelled by jealousy and revenge.
The following day, Roper took Ms Tovizi's laptop, cellphone and bank card, and put her three-year-old son in her Subaru Legacy car and drove off.
The Crown says he tried to sell the laptop to an associate for $150, before dropping Ms Tovizi's young child off at his great-grandparents' house, telling them that Ms Tovizi had "done a runner".
After she was found on December 9, Roper constantly lied to police and others over Ms Tovizi's whereabouts, Mrs Currie said.
And once he was arrested in February 2011, he made admissions to police, saying, "Yeah, I killed her".
During a police interview he said he helped drown her because she wanted to kill herself.
"Helping someone kill themselves is still murder ... that doesn't give you an out," Mrs Currie said.
Roper also told fellow prison inmates that he had killed Ms Tovizi, and spoke of a sleeper hold and of drowning, the court heard.
Mrs Currie said Roper also had a familiarity and awareness of the sleeper hold and its consequences.
"He had a fascination with the sleeper hold," she said.
The trial had also heard evidence that he had attacked her neck or throat on three previous occasions, including at Cowles Stadium in August 2010, which resulted in him being jailed.
