Madeleine Pulver's relief at seeing her attacker jailed is "incredible", her dad says, but she may never know why she was targeted by the hoax collar bomber.
Paul Douglas Peters, who cornered the teenager in her bedroom last year, was yesterday sentenced to 13-and-a-half years in jail, and must serve at least 10 of them.
It marks the end of a bizarre and puzzling crime, but many questions remain unanswered.
Sentencing Peters in Sydney's District Court, Judge Peter Zahra noted: "There will always remain some uncertainty as to the reasons he decided to engage in an act of extortion involving violence of substantial gravity".
On August 3 last year, Peters - a wealthy businessman based mainly in the US - entered the Pulver family home in Mosman on Sydney's north shore, wearing a multi-coloured balaclava and armed with a baseball bat.
Ms Pulver was studying in her room for her HSC when he placed the hoax bomb around her neck.
A document attached to the device demanded an unspecified sum of money and said tampering with it would make it explode.
After a 10-hour ordeal, the device was confirmed as a hoax.
Peters was arrested in the home he shared with his ex-wife in Louisville, Kentucky about two weeks later and extradited to NSW.
In March, he pleaded guilty to aggravated breaking and entering and detaining with advantage.
During sentence proceedings, the court had been told Peters suffered from severe depression and bi-polar disorder, and that he claimed to have no memory of attaching the device to Ms Pulver's neck.
He told one psychiatrist he had "no idea" why he chose the Pulver home, saying he had never met Ms Pulver in his life.
The court heard he had taken on the role of a character in a book he was writing, and had intended to be caught.
"The end game was quite simple," Peters told one psychiatrist.
"To get caught, to stop drinking and to be in front of a psychiatrist, as well as assisting my novel."
Crown prosecutor Margaret Cunneen, SC, submitted it was a deliberate extortion attempt and Peters in fact entered the wrong house.
The court heard Peters was tracking down the beneficiary of a multi-million dollar trust, but his target changed when he recognised a neighbour of the Pulvers from his Hong Kong business dealings.
Peters mistakenly believed he was entering that man's house on August 3 when he committed the "act of urban terrorism", Ms Cunneen said.
Judge Zahra said it was difficult to assess Peters' motive as he did not give evidence during the sentence hearings.
He said he did not believe Peters was suffering from a substantial mental impairment at the time, although he may have been depressed.
"He would have appreciated the enormity of what he was doing," the judge said, adding he would have instilled "unimaginable" fear in the 18-year-old.
"(Peters) intended to place his very young victim in fear she was going to be killed," he said.
Ms Pulver and her parents, Bill and Belinda Pulver, shed tears as the sentence was handed down.
Peters remained expressionless.
Outside court, Madeleine Pulver said she was pleased it was over.
"I can now look forward to a future without Paul Peters' name being linked to mine," she told reporters.
"We feel an incredible sense of relief today," her father added.
Peters had never apologised or given an explanation for what he did, Mr Pulver said.
"There's only one person in that room who really knows why Maddy ended up at the receiving end of his device," he said.
Taking into account time already served, Peters will be eligible for parole in August 2021.