True Crime

Devil mum forced her boys to kill their sister

When a young woman reported her mother to the police, her story was so horrifying they didn’t believe it was true.

Theresa Knorr was just 18 when she was cleared of murdering her husband. The judge found it was self-defence.

Surely this tearful teenage mum-of-one, pregnant with her second child, wasn’t capable of such a cold-blooded killing?

But Theresa was capable of murder, and the most unimaginable cruelty…

As well as son Howard, she went on to have Sheila, followed by Suesan, William, Robert, then little Theresa, known as Terry. With four failed marriages behind her, she was raising the kids alone and drinking heavily.

‘She stopped going out,’ William recalled later. ‘She got rid of the telephone because she didn’t want any people calling. We weren’t allowed to have anybody inside the house.’

By isolating herself and her children, Theresa ensured they had no-one to turn to when she burnt them with cigarettes and tortured them.

So jealous that Sheila, Suesan and Terry had youth and beauty on their side while she was growing older, Theresa force-fed the girls to fatten them up, sometimes breaking their teeth, to make them unattractive.

Howard had fled as soon as he was able, so Theresa set about training William and Robert to hold their sisters down and beat them. If they refused they suffered a beating themselves.

She even threw steak knives at them and held a gun to Terry’s head.

‘The next morning I woke up and I still had a knot from where the barrel had sunk into my temple,’ she said later.

Terry
Terry reported her mum

Desperate, Suesan tried running away, but was found by a truancy officer and forced to return home. Her punishment was the worst beating she’d ever received, with Theresa making all the children take turns holding her down and punching her in the stomach.

‘I had to hit her twice because I didn’t hit her hard enough the first time,’ Robert recalled later.

When Suesan was 17, Theresa shot her in the chest.

Miraculously, she survived and a year later, fed up with the constant abuse, she told her mother that she wanted to move out.

Theresa agreed, but only if they removed the bullet still lodged inside her to eliminate proof of the shooting.

Knocking Suesan out with a cocktail of medication and alcohol, Theresa forced 15-year-old Robert to try to retrieve the bullet. Within days, Suesan developed an infection that left her jaundiced and delirious.

Claiming Suesan was possessed by Satan, Theresa instructed William and Robert to dump their sister and douse her in petrol.

Terrified of their mother, they helped her burn Suesan alive. Her body was discovered soon after but her remains couldn’t be identified. Next, she forced William and Robert to beat Sheila and lock her in a cupboard. ‘Help me, help me,’ Sheila cried, but none of the kids dared open the door. Eventually the cries stopped and Sheila died of starvation and dehydration aged 20.

When the smell of her decomposing body became too much to bear, Theresa made the boys dump it.

Her remains were found, but with no-one reporting her missing, she too became listed as a ‘Jane Doe’.

Aged 15 and frightened of becoming the next victim, Terry ran away. William also made his escape, but Robert stayed by Theresa’s side.

In 1989, Terry mustered the courage to approach police. She told them everything her mother had done, but her story was so gruesome and outrageous that police accused her of spinning a tale.

Four years later, aged 23 and now a mother herself, Terry tried again.

This time, officers remembered finding the remains of two unidentified young women almost 10 years earlier. A task force soon gathered evidence – and all of it pointed to the truth. William, who was living a quiet life, was arrested. Robert was also tracked down, serving time for an unrelated murder.

Both men corroborated Terry’s account of their years living under the rule of their evil mother. Police dubbed her ‘the woman with no soul.’

William
William was forced to abuse his siblings

Detective sergeant John Fitzgerald asked William why he and Robert didn’t stand up to Theresa.

‘His response was, “You don’t know what it was like to live in that house. You have no idea what it was like,”’ the detective said.

At first, Theresa denied the allegations, but when she found out William and Robert had told police everything, she changed her plea to guilty.

She was ordered to serve two life sentences at a California jail and will be eligible for parole in 2027 when she’s 80. William was sentenced to probation and ordered to undergo therapy for participating in Sheila’s murder.

In exchange for his testimony, the prosecution dropped all charges against Robert except for one count of being an accessory after the fact to Sheila’s murder. Terry said she wished she could have saved her sisters before it was too late.

For all the siblings, trying to survive in that house of horrors took its toll.

‘I grew up in an insane asylum,’ Robert explained. ‘But what’s worse is we didn’t know it was an insane asylum. I never really knew that I was being abused. I thought it was normal.’

Read more in this week’s issue of that’s life!, on sale now.

Related stories