A serial child sex abuser will spend more time behind bars after he admitted tricking his daughter's friend with a sick game.
The 63-year-old, whose name is forbidden from publication, was sentenced in the ACT Supreme Court on Wednesday to 18 months in jail after pleading guilty to a charge of sexual intercourse with a child.
Justice David Mossop ordered that six months of the latest punishment overlap with an existing 12-year jail term, increasing the man's total prison sentence to 13 years.
The judge also increased the offender's previous six-year non-parole period by five months.
Justice John Burns imposed the original sentence in 2020, after a jury found the Canberra man guilty of historical child sexual offences involving three nieces.
Those crimes were committed between 1979 and 1990, when the victims were aged between five and 15.
On Wednesday, the court heard a fourth victim had contacted police since the original sentencing.
The woman told investigators she would go to the offender's home to play with the man's daughter.
She was eight or nine at the time in question, in the mid-1990s, and the offender's daughter was a similar age.
On one occasion, the victim went to the offender's house to find her friend was not there.
The offender asked her if she wanted to play a game that involved her closing her eyes.
When she opened them, she found him sexually abusing her.
The victim was afraid to tell her mother about what had occurred, but she eventually did when she was 16.
It was a few decades, however, before she went to police.
On Wednesday, prosecutor Greta Cuthel noted this was common in cases of child sexual abuse.
She told the court the 63-year-old had, since the offending, spent decades in the community without repercussions, but the victim had suffered the effects of the crime the entire time.
Ms Cuthel argued it was important to bring perpetrators to justice even though they may be old and frail by the time their victims felt able to disclose the abuse.
She made this submission after defence lawyer Jonathan Cooper asked Justice Mossop to be lenient in light of the offender's many health issues.
Mr Cooper outlined how, after a series of strokes last year, the 63-year-old now used a wheelchair but required help to move it.
He also needed assistance, Mr Cooper said, with simple tasks like showering and going to the toilet.
"What we know is that he wets himself," Mr Cooper told the court.
"Mobility: he needs someone to push him in the wheelchair.
"There's also eating. He needs certain foods, with a big spoon, to be able to eat."
As the offender listened over the phone and the victim watched from the court's public gallery, Justice Mossop described the crime as "a gross abuse" of the power imbalance between an adult and child.
The judge noted the offender, a former bus driver and "house husband", claimed to have no memory of the incident in question.
The sentence that was ultimately imposed makes the 63-year-old eligible for parole in July 2026.
Justice Mossop said the man's ill health meant he was "effectively disabled from future offending".