SYDNEY -- Police were hunting Thursday for a masked man who chained a fake bomb to a young woman's neck after breaking into her wealthy family's home in an extortion attempt that Australia's prime minister said resembled "a Hollywood script."

In a climactic scene late Wednesday, bomb squad specialists safely freed Madeleine Pulver after 10 harrowing hours with the device attached around her neck. The 18-year-old was not hurt and police later determined the device contained no explosives.

A note of demands had been attached to the device, New South Wales state Police Detective Superintendent Luke Moore said, though he declined to specify what the demands were.

"We are treating this as an attempted extortion -- a very serious attempted extortion," Moore said.

The drama began on Wednesday afternoon in the upscale Sydney suburb of Mosman when Pulver's family contacted police saying their daughter had been attacked and there was a strange device attached to her. Bomb technicians, negotiators and detectives rushed to the scene. Neighboring homes were evacuated, streets were closed and medical and fire crews waited nearby.

Pulver told police a man wearing a mask broke into her home and confronted her while she was in the kitchen. The teen said the man forced her to stay still while he fitted the device to her neck, and then fled. When officials arrived on the scene, they found Pulver alone in the house with the suspicious device tethered to her neck by a chain.

The family lives in one of Sydney's ritziest areas and her father, William Pulver, is CEO of an information technology company. On Thursday, he fought back tears as he talked about his daughter's horrifying ordeal.

"We as parents are extraordinarily proud of Maddy," William Pulver said, his equally tearful wife Belinda at his side. "I think she has woken up this morning in pretty good spirits. She's a little tired, a little sore, from holding this damned device in place for about 10 hours."

Forensics officers spent Wednesday night combing through the family's three-story home and scouring the surrounding streets for evidence. Moore said they had not identified a prime suspect and are trying to figure out how the man got into the house.

"We are treating this as an individual incident," Moore said. "We have absolutely no information to suggest this is linked to any other crime."

New South Wales state Police Assistant Commissioner Mark Murdoch said the device was quite sophisticated and was designed to look like a bomb as part of a "very, very elaborate hoax."

Prime Minister Julia Gillard said she was shocked when she heard about the case on Thursday.

"When I looked at it this morning, the first thing I said was, 'It's like a Hollywood script -- the kind of thing you would see at the cinema or on TV,"' Gillard told Fairfax Radio. "You would never expect it to happen in real life in Australia."

Pulver was examined and released from a Sydney hospital on Thursday. Students at the private girls' school she attends were being offered counseling.

"The school community is united behind the student and her family, and we thank God that she is not hurt," Wenona School officials said in a statement.