A child sexual assault victim repeatedly let down by the court system has described being re-traumatised as it took more than a decade for her abuser to be convicted.

Former police officer Mario Simon Didluca, 51, appeared in Victoria's County Court by video link from prison for a pre-sentence hearing on Tuesday, after he was found guilty of sexual penetration with a child under the age of 16.

He committed the offences against a 14-year-old girl in 2010 but was not arrested for another eight years, when he was living overseas to support his teenage son, a professional soccer player.

Didluca then spent 99 days in one of the world's worst prisons, after Australian authorities put out an INTERPOL red notice for his capture.

The Bosnian jail was featured on an TV series about "horrific prisons", his barrister Georgina Connelly said, and inmates targeted Didluca after finding out he was a cop charged with child sexual offences.

"If one were to draw an ancient prison - damp on the walls, made of stone - this fits that description," she said. 

He was not properly protected by prison guards and experienced persistent violence, which severely impacted his mental health, she said.

Once extradited to Victoria, his case was subject to further delay.

Didluca's first trial was listed to begin in October 2021, but was abandoned days before due to COVID-19 lockdowns.

A new trial was set for March 2022, but Didluca contracted COVID-19 himself and it had to be adjourned. Then, a third trial was scuppered after a media organisation inaccurately reported on the case.

In March this year, a jury found Didluca guilty of two charges of sexual penetration with a child under 16 and not guilty of five other charges.

The girl said she had been re-traumatised by every hearing and mistrial, but was relieved he was finally found guilty.

"It has been traumatic giving evidence, presenting my most exposed and vulnerable information," she told the court.

"I feel like the system has let me down over and over again."

When he was released on bail, in 2019, she said she lived in fear for four years. He was taken back into custody following the jury verdict.

Judge Liz Gaynor said the 12-plus years before conviction was extraordinary and slammed prosecutor Peter Triandos in court for failing to properly explain the reasons for it.

"You better start telling me why this sort of delay took place because I regard it as unconscionable," she said.

Mr Triandos admitted the delay was lengthy and said an initial red notice in 2016 expired after two years. Didluca was then arrested by Bosnian authorities when he crossed the border with Croatia.

Didluca was working as a police officer at the Operational Response Unit at the time of the offending in 2010.

Ms Connelly said he was seeking a boost in self-esteem from his relations with the young girl, as he felt like his wife was not attracted to him.

Didluca will be sentenced on June 9.

1800 RESPECT (1800 737 732)

National Sexual Abuse and Redress Support Service 1800 211 028