An Israeli former principal will spend up to 15 years in jail for sexually assaulting two students at an ultra-Orthodox Jewish school in Australia.

Malka Leifer raped and indecently assaulted sisters Dassi Erlich and Elly Sapper between 2003 and 2007, a jury found in April.

The 56-year-old was found not guilty of abusing a third sister, Nicole Meyer.

Leifer’s sentencing ends a 15-year push for the mother-of-eight to face justice.

She had pleaded not guilty to more than two dozen charges and spent years fighting extradition from Israel. But in 2021, an Israeli judge found she had faked mental illness to avoid facing the courts and ordered she be sent to Melbourne.

During a lengthy trial, the jury heard evidence that Leifer had abused the sisters in locked classrooms, on school camps, and at the head teacher’s home.

Detailing the 18 charges on Thursday, judge Mark Gamble called her offending “insidious”.

Leifer was a revered figure at the Adass Israel School, awed almost like a rabbi, he said. And the sisters were starved of love and in need of protection – emotionally and physically abused at home by their mother and completely uneducated about sex.

“This case is striking for just how vulnerable these victims were, and for the calculating way in which the offender, Mrs Leifer, took callous advantage… for her own perverse sexual gratification,” the judge said.

Addressing “powerful” victim impact statements from Ms Sapper and Ms Erlich in which they spoke about lasting feelings of guilt, shame and fear, Judge Gamble stressed they were “completely innocent” of the “predatory behaviour” of Leifer.

“It is she and she alone who should feel guilty and ashamed for what occurred.”

Considering the time she has already served in prison, Leifer will be eligible for parole in June 2029.

Speaking alongside her sisters outside court, Ms Erlich said the sentence was the end of a long and traumatic chapter of their lives.

“We are here today because we did not give up,” she said.

“And while we know that the onus of fighting for justice should not be up to survivors, this fight was never just for us.

“To any other survivors in this nightmare: you are never alone, we are all behind you.”

Now Leifer’s trial has concluded, police have reopened an investigation into her attempts to evade justice.

The headteacher fled to Israel in 2008 after accusations were raised against her, reportedly with the help of members of the school board. She was arrested at Australia’s request in 2014, but two years later an Israeli court suspended her extradition, ruling her to be mentally unfit for trial.

But undercover private investigators later filmed her shopping and depositing a cheque at a bank, leading Israeli authorities to investigate and re-arrest her in February 2018. A judge there said she had been “impersonating someone with mental illness”.