"He was my only sibling and last surviving member of my immediate family," she said.
The Herald can reveal that in 1992 the siblings' mother, Ildiko Matskassy, was killed and her body later found in Wellington Harbour.
The 28-year-old was strangled and her skull was fractured before she was dumped in the water on November 26 1992.
Her husband, Ivan Matskassy, 42, was charged with murder, however, he was found not guilty after a trial at the Wellington High Court.
After Mrs Matskassy's death, her children were put into foster care. Ms Matskassy was 12 and her brother 9 at the time.
They eventually returned to live with their father and the trio moved to Australia.
According to the Daily Mail the Supreme Court heard yesterday that Mr Matskassy and Darrington were fighting over a gun when the weapon discharged.
Police say its shot most likely killed Mr Matskassy.
As Mr Matskassy lay on the floor, bloodied and lifeless, Darrington shot him again.
Darrington was drunk at the time, his lawyer told the court, and in shock. He believed Mr Matskassy was "all but fatally wounded" and shot him in the head to put him out of his misery.
"He makes the extremely poor decision to fire off the second shot," the lawyer said.
Justice Paul Coghlan said it was an irrational response.
He said Darrington intended to kill Mr Matskassy and believed he was alive at the time he shot him.
Darrington could have called emergency services or taken Mr Matskassy to hospital but instead, he aimed and fired at the man.
The court also heard that before the shooting, Mr Matskassy and Darrington had an argument at an associate's home.
During the argument Darrington assaulted Mr Matskassy.
The defence claimed Mr Matskassy produced the gun but Justice Coghlan said he could not rule out where the weapon had come from.
Darrington will be sentenced early next year.
