Canadian killer Karla Homolka, is one of the world's most notorious female criminals. In the early 90s she and her husband Paul Bernardo raped and killed three teenage girls - including Homolka's own 15-year-old sister. So how on earth is she now being allowed to volunteer at a primary school?

It was the case that shocked Canada and indeed, the whole world. Pretty blonde Karla Homolka was just 20-years-old when she and her then boyfriend Paul Bernardo raped and killed her younger sister Tammy, 15, while her parents slept upstairs. The reason? Bernardo was angry that his girlfriend wasn’t a virgin, and demanded Homolka let him take her teenage sister’s virginity instead. So the pair made a sick pact to drug and rape Tammy. The warped couple even filmed their attack, which involved Homolka sexually assaulting her own sister. Tragically Tammy died after choking on her own vomit. Incredibly the killer pair got away with their crime, with the autorities assuming it was just youthful drinking gone wrong.

Paul Bernardo (R) Getty Images

And perhaps Homolka and Bernardo, who later got married, would have been able to keep their sick crime secret forever if they’d not killed and raped again, and again.

In 1995 the pair were finally hauled before the courts. But in a hugely controversial move, Homolka was jailed for just 12 years for her part in the killings in a plea bargain that saw Bernardo jailed for a minimum of 25 years. There was uproar, particularly after videos surface that showed Homolka had taken a much more sadistic and active role in the crimes.

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She was finally released from prison in 2005 again to much uproar. One of Canada’s most notorious criminals, no one wanted Homolka living in their neighbourhood. But despite her sinister past, Homolka seems to have a pretty happy life. Now divorced from Bernardo, Homolka married her lawyer’s brother, and had three children, before settling down to a life of domestic bliss in Montreal.

But controversy is never far away from the infamous serial killer. This week it emerged that the Homolka sometimes works as a volunteer at Greaves Adventist Academy – the Christian school her children attend. Reports suggest she recently helped supervise young children on a field trip, has helped teached some children to knit, and even took her dog into the school for the children to pet.

When approached by reporters Homolka became angry, threatening them with her lawyers. ‘I don’t have nothing to say,’ she said.

Parents at the school however have plenty to say. They’re outraged that such a callous killer is allowed to walk freely among their kids.  One parent, Andy Maraj, only found out the truth after another parent handed out leaflets about Homolka.

‘I told my daughter – ‘this lady, I don’t want you to go near her please,’ Andy said. ‘If she calls you, don’t go near her and call me,’ because I don’t trust the school.’

Another parent put it more bluntly.  ‘We don’t want her here. How would you feel knowing that your child is interacting with a person who is a serial killer?’

And the story doesn’t end there. Homolka’s sadistic accomplice Bernardo is currently making a bid for parole. Find out why Bernardo should NEVER be released by reading the gruesome details of the case here.