Peters told the examining psychiatrist that he as became more involved in his book he took on Chan's persona. According to court documents, "he said the suburb of Mosman was like the Hong Kong peak and he wanted to create in his own mind what the nemesis in his book could have been doing."

During sentencing, the judge debunked suggestions that Peters was motivated by a confused reality and said the motive, beyond reasonable doubt, was extortion.

"The offender intended to place the very young victim in fear that she was going to be killed in order to ensure compliance with the directions in the demand. The offender did so in order to extort money from the victim," Judge Zahra said.

The plan ultimately failed, the judge said, because police were called, the media was alerted, and Peters decided to abandon his efforts to extort money.

Five days after entering the house, Peters flew from Sydney to Los Angeles before boarding a connecting flight to Louisville, Kentucky. He was arrested there on August 15 and later extradited to Australia.

It remains unclear why Peters targeted an 18-year-old girl and it would be "unproductive to speculate," said Judge Zahra.

Outside the court, Bill Pulver said of his daughter: "Maddie Pulver is a very, very special young lady who has handled herself with incredible poise and dignity. We're unbelievably proud of her."

Peters was sentenced to 13 years and six months in prison, with a non-parole period of 10 years.