The father of a teenager who spent 10 hours in a Sydney mansion with a fake bomb chained around her neck revealed Wednesday he might not have called the police had he known it carried an extortion note.

Bill Pulver told reporters he might have paid the unspecified ransom rather than call the police to avoid risking his daughter's safety further.

Pulver was speaking outside the New South Wales state District Court, where investment banker Paul Douglas Peters, 52, appeared for a sentencing hearing after pleading guilty to charges of breaking into the Pulver residence and committing a serious offense. He faces up to 20 years in prison when the hearing continues Nov. 7.

"If I had known there was an extortion letter, I ask myself the question: Would I have actually rung the police?" Pulver, a wealthy software businessman, said. "I'm really not sure what I would have done," he added. "He very nearly got away with it."

Peters admitted to entering the family mansion wearing a ski mask and wielding a baseball bat on Aug. 3, 2011 before tethering a harmless devise to then-18-year-old Madeleine Pulver, who had been home alone studying for high school exams.

The teen telephoned her father after Peters left the house, unaware that a note was attached to the fake collar bomb demanding an unspecified sum of money and warning that the device would explode if tampered with.

Bill Pulver raised the alarm, sparking a 10-hour police bomb squad operation that determined the device was harmless, and subsequently discovered the ransom note.

Peters, who traveled frequently between the United States and Australia on business, fled to the U.S. and was arrested nearly two weeks later at the Louisville, Kentucky, home of his former wife, Deborah Peters. He was extradited to Australia and has remained in prison custody since.

Two psychiatrists on Wednesday gave differing opinions on Peters' mental state at the time of the incident, which Peters has said he has no memory of.

Psychiatrist Jonathan Phillips testified that he believed Peters was in a psychotic state during the crime. Peters was one of the most difficult and complex cases he had ever assessed, he said.

"It's unusual for a person with a long and seemingly untroubled life and record to then commit an extremely callous and dangerous act," Phillips said.

Phillips said Peters suffered from a bipolar disorder and was in an intermittent psychotic state in the weeks or months prior to the incident.

Psychiatrist Stephen Allnutt said he did not believe Peters was suffering from psychosis.

"When you look at the (police) interview ... he's a fairly intelligent man who doesn't demonstrate any symptoms of mental illness," Allnutt said.