SYDNEY (AFP) ― An Australian investment banker who attached a fake bomb around the neck of a Sydney schoolgirl in a bid to extort money from her wealthy family was Tuesday jailed for at least 10 years.

Paul Peters, 52, who was arrested and extradited from the United States in September last year with the help of the FBI, pleaded guilty to aggravated breaking and entering, and detaining the teenager for advantage.

The father-of-three made global headlines when he broke into the multimillion-dollar Pulver family home wearing a mask and strapped a device to 18-year-old Madeleine’s neck with a note claiming it was a bomb in August 2011.

A Sydney court heard he was suffering psychiatric problems after his marriage broke down and he lost custody of his children, with the judge saying he appeared to think he was an “avenging character” in a novel he was writing.

He told doctors he had wandered Sydney’s leafy harbor suburbs, seeking to “relive scenes in the book” ― set in Hong Kong ― and eventually came to believe he was one of the protagonists, John Chan.

He fixed the hoax collar bomb to Pulver as part of a plan to exact what he described as a “dual revenge; one for John and one for me.”

Police, bomb squad and other emergency services descended on the scene and Pulver endured a horrifying 10-hour ordeal with experts working into the night to remove the device, only later establishing it was an elaborate hoax.

Pulver was in court to watch Judge Peter Zahra jail Peters for a maximum 13-and-a-half years and said she was “pleased with today’s outcome and that I can now look to a future without Paul Peters’ name linked to mine.”

“I realize it is going to take quite some time to come to terms with what happened, but today was important because now the legal process is over,” the teenager added to reporters outside court.

“For me it was never about the sentencing but to know that he will not reoffend, and it was good to hear the judge acknowledge the trauma that he has put my family and me through.”

Her father, Bill, said there was a “great sense of relief” for the family.

Zahra, who said Peters would be eligible for parole in 10 years, described his bizarre crime as “heinous” and a “deliberate act of extortion” which had terrified Pulver, now aged 19, who was home alone studying for exams.

“The offender entered a house armed and disguised. He found the young girl on her own and vulnerable,” Zahra said.

“At the time of placing the device he had prepared around the neck of the victim he would have appreciated the enormity of what he was doing and the terrible effect and consequence of his conduct upon the victim,” he added.

Zahra said Peters “would have been aware that after he left the victim she would have experienced considerable trauma before it was determined that the device did not contain explosives.”

“He would have understood, at the time, in the many hours that followed she was in fear she would be killed,” he added.

“The terror instilled can only be described as unimaginable.”

Zahra noted that Peters’ expressions of remorse had been “qualified and guarded” and gave him “minimal” discount for his mental health problems, which included bipolar disorder, alcohol abuse and major depression.

Prosecutors had described the sensational case as an act of “urban terrorism” fuelled by financial greed.