|Madeleine Pulver was detained in her home by Peters with a fake explosive strapped to her neck last year [Reuters]
An Australian man has pleaded guilty to chaining a fake bomb to a young woman's neck in an extortion attempt last year.
Paul Douglas Peters' lawyer pleaded guilty on his behalf in a Sydney courtroom on Thursday, to a charge of "aggravated break and enter and committing a serious indictable offence" by knowingly detaining 18-year-old Madeleine Pulver.
"Mr Peters deeply regrets and is profoundly sorry for the impact that this incident has had on Ms Pulver and her family," Kathy Crittenden, the lawyer, told reporters after the hearing.
Peters, an investment banker, appeared in court by video from prison on Thursday. He showed no reaction when his lawyer entered the guilty plea.
Pulver was alone studying in her family's Sydney home on August 3 when Peters, wearing a ski mask and wielding a baseball bat, tethered a bomb-like device around her neck.
It took police 10 hours to remove it, but it contained no explosives and Pulver was not injured.
Peters, 51, left behind a note demanding money, along with an email address.
New South Wales state police have said surveillance footage showed Peters in several locations where they believe he accessed the email account.
Peters, who travelled frequently between the United States and Australia on business, fled to the US and was arrested at his former wife's home in Louisville, Kentucky, almost two weeks after the incident.
He was extradited in September to Australia, where he has remained in custody.
'Wrong place at the wrong time'
US federal court documents show Peters once worked for a company with links to her family, but the Pulvers have repeatedly said they do not know him.
Madeleine Pulver was in court with her parents to hear the plea. Her father, Bill, thanked police, prosecutors and members of the public for their support, and said the attack remains as mysterious and as "random to us in our minds as it did back on August 3."
"There was... nothing other than just the fact of Maddie was in the wrong place at the wrong time," he said outside court.
According to Australian court documents, Peters entered the Pulvers' home through the unlocked front door and confronted the teen in her room. "Sit down and no one needs to get hurt," he told her.
He then attached the bomb-like device, a two-page typed letter and a USB stick to her neck, told her to count to 200 and left.
In the letter, Peters warned officials not to tamper with the device or it would explode. He said he would send further instructions for a "defined sum" of money, and in exchange, would provide the code to unlock the device.
"I am a former Special Forces Green Beret munitions specialist and have constructed such devises for over twenty years," the letter said. "SO, ACT NOW, THINK LATER, or YOU will inadvertently trigger a tragically avoidable explosion, known in the American armed forces, as a BRIAN DOUGLAS WELLS event."
Wells was a Pennsylvania pizza delivery driver who was killed by a bomb that was locked around his neck as part of a bank robbery plot in 2003.
Peters will appear in court next on March 16 for a pre-sentencing hearing. He faces up to 20 years in prison.