'Bomb' Threat To Girl: No Explosives Found

Police say no explosives were found on a device that was reportedly strapped to the neck of a teenage girl for 10 hours in a 'bomb' threat in Australia.

Bomb squad experts were able to release Madeleine Pulver, 18, from the "very elaborate and sophisticated" device after getting advice from federal police and the British military.

The perpetrator, wearing a balaclava, entered the multi-million dollar Sydney property shortly after 2pm (local time) on Wednesday and then placed what was reported to be a "collar bomb" around the girl's neck, it was claimed.

He said she could call police but not reveal too much information about him or their conversation, said the Sydney Daily Telegraph.

He indicated he had planted listening devices and said unless she was limited in what she told officers, he would remotely detonate the "bomb", the paper added.

With the device secured, the man then left and the girl, who was alone, telephoned police in a frantic call about 2:30pm.

Experts from the New South Wales (NSW) bomb squad spent a number of hours inside the house which is in the upmarket suburb of Mosman.

They examined the device while it remained secured around the teenager's neck, and neighbouring properties were evacuated.

During the drama in the Australian city, Ms Pulver was fed, given water, kept warm and looked after by specialist police officers.

Assistant Commissioner Mark Murdoch said she was "kept in an uncomfortable position" during the "unusual incident" and was later taken to hospital to be assessed.

Police said the device was still intact and was undergoing a forensic examination.

"She (Ms Pulver) has disclosed a lot of information to police. That information will now be acted upon," Mr Murdoch said.

"The family are at a loss to explain this. You would hardly think someone would go to this much trouble if there wasn't a motive behind it."

He said the parents were "immensely relieved" after being reunited with their daughter, and police have not yet established a motive for the incident.

Mr Murdoch said officers were looking for the person who they believe placed the device, adding: "We want to get our hands on who's done this".

He said he was not aware of "anything like this happening in NSW or this country before".

One line of inquiry is whether she was the victim of an extortion attempt to extract money from her businessman father, Bill Pulver, who is the chief executive of a leading technology company.

Mr Murdoch said it was "far too early to say" whether the device was part of an extortion bid and refused to comment on a report that a note was left with the device.

The investigation is being led by the robbery and serious crimes squad, which also deals with extortion attempts.

The Sydney Daily Telegraph cited a senior police officer referring to the device as a "collar bomb".

Mr Murdoch said the device was placed near her - but refused to confirm reports the device was tethered to her body.

Speaking to the Sydney Daily Telegraph, security specialist Justin Bowden said that the necklace bombs, as they are also known, had been used in extortion cases in Mexico and Colombia. Similar devices had also been utilised in Israel.

"These devices are usually made from crude materials. You can make them from nothing more than pieces of canvas, which are then stacked with small pouches filled with explosives," he told the newspaper.

"One of the reasons they are used is that they are closer to the head and neck and you don't need a large amount of explosives."