Media playback is unsupported on your device Media caption The prosecution think Paul Peters may have targeted the wrong house

A man who locked a fake bomb around the neck of a teenage girl in an apparent extortion attempt has been jailed for 13-and-a-half years by an Australian court.

Paul Douglas Peters attached his fake device to Madeleine Pulver, then 18, at her home in Sydney in August 2011.

It took police and experts 10 hours to analyse the device and declare it safe.

Peters admitted the charges in March 2012 after being extradited from the US.

A former investment banker, he was arrested at the home of his ex-wife in Louisville, Kentucky.

'Revenge novel'

Judge Peter Zahra said Peters had put his young victim through "unimaginable" terror.

Image caption Madeleine Pulver spent 10 hours with the fake device attached to her

Lawyers for the defendant had argued that the collapse of his marriage had caused depression.

They also argued that, at a time when he was drinking heavily, he had become obsessed with a novel about revenge that he was writing and had confused reality with fiction.

But prosecutors said Peters' aim was extortion and that he entered the wrong house, with his intended target living next door.

Peters was given a sentence of 13 years and six months, with a 10-year non-parole period.

Speaking outside the court, Madeleine Pulver said she was grateful to the judge for acknowledging the trauma she and her family had experienced.

"I realise it will take quite some time to come to terms with what happened. But today was important because now the legal process is over," she said.