A former nurse who filmed and photographed himself sexually abusing 47 boys across Southeast Asia and Australia will spend at least 28 years behind bars.
A depraved Melbourne paedophile filmed and photographed the abuse of almost 50 boys across four counties, telling one victim to smile as he raped him.
Boris Kunsevitsky has been jailed for at least 28 years, after taking more than 35,000 photos and 4800 videos of the abuse in the Philippines, Singapore, Indonesia and Australia between 2002 and 2017.
Supreme Court of Victoria Justice John Champion told the 53-year-old former emergency nurse it was the worst case of child sexual abuse he had seen.
"You are a child abuser of appalling ... proportions," the judge said in sentencing him to a maximum of 35 years behind bars on Wednesday.
He labelled Kunsevitsky's crimes as the "remorseless use of vulnerable children for your own depraved gratification" and said the paedophile's appetite for sexual abuse appeared insatiable.
He mostly targeted disadvantaged boys in the Philippines, performing sexual acts on them, sometimes while they slept, and making them perform similar acts on him as well as each other.
Kunsevitsky filmed and photographed it all, and in one of the videos told a victim who was in visible pain to smile as he raped him.
"You chose destinations where you could easily and readily access young boys," Justice Champion said.
The abuse also occurred at Kunsevitsky's Singapore home, in Indonesia and Melbourne.
Some of his victims in Asia have not been identified.
After being caught by police upon his return to Australia in 2017, Kunsevitsky blamed the children he abused.
One of them was a 13-year-old Melbourne boy, groomed by the paedophile online.
His abuse lasted for about two years over 2004-05, before German police found 55 pornographic images of the boy online inside a folder labelled "jailbait".
Kunsevitsky was never charged with distributing child pornography and in March 2019 pleaded guilty to 59 offences.
They included engaging in sexual intercourse with a child under 16, both within and outside Australia, producing child pornography, and causing a child to engage in sexual intercourse in his presence and with another person.
His Australian victim later attempted suicide and developed drug problems which led to him being $100,000 in debt.
He also suffered a breakdown which cost him his job and marriage.
In a statement to the court, the victim said he had been too young to understand what was happening at the time, but the abuse made him feel gross and stupid.
He said Kunsevitsky controlled him, convinced him no one else cared, and left him feeling used and disregarded when, at age 15, the abuse stopped.
"There is no sentence that I can pass that will undo the tremendous pain you have caused (the victim)," Justice Champion told Kunsevitsky.
Despite being caught with 35,344 abusive images and 4810 videos on a mobile, laptop and USBs upon his return from Southeast Asia, Kunsevitsky initially denied the abuse.
The photos and videos were "difficult to look at" and "deeply disturbing, sordid and sad", Justice Champion said.
Kunsevitsky told police he travelled to the Philippines often, where he helped several families, and said children had used his video equipment while they were showering.
He later told a psychiatrist his victims had been active protagonists in their abuse and that their families supported it.
He added he had sought "that one special person".
The paedophile has an IQ of 125, suffered a traumatic childhood and was described as having near-delusional beliefs about the abuse he inflicted on 47 children.
Kunsevitsky has since been diagnosed with a paedophilic disorder, alongside a substance abuse disorder.
He also has symptoms of a mood disorder and is at risk of self-harm behind bars.
Justice Champion said the abuser's "twisted beliefs" must be denounced and was uncertain as to whether he could be rehabilitated.
Lifeline 13 11 14
beyondblue 1300 22 4636