Aussie mystery solved – Missing for 15 years but she was buried in the backyard

Here, Jon Knowles, 74, tells the story in his own words.

Tearing open the envelope, a flash of colour caught my eye.

Living interstate, my girl Trish wrote me a weekly letter, always tucking in drawings from her four young children.

Their masterpieces were usually just rainbow scribbles. But, a proud pop, I kept every single one!

Then in August 2001, Trish, 34, her husband Ian and their kids moved from Canberra to Margate, a beachside suburb near Brisbane.

Now just an hour away from my farm, I got to see them all the time.

But after 17 years of marriage, Trish was having a tough time.

‘I’ve enrolled to study business management at uni,’ she told me that September.

As well as home schooling the kids, my girl was a swim coach. But Ian wasn’t working and Trish felt like she needed a better job to support them all.

I let Trish know I was there for her.

Three days later, on a Wednesday night, Ian called. ‘Is Trish there? She’s walked out,’ he said.

Apparently, she’d taken her phone, keys and credit card, but left her purse. That doesn’t make sense, I thought.There was something chilling about Ian’s calm, collected tone.

Driving around the next day to check on the kids, aged 14, 11, nine, and seven, I was shocked to find Ian had already given most of Trish’s clothes to a charity shop.

Even if you lost a dog, you’d go looking for it, I thought.

But Ian didn’t seem to be at all bothered about finding his wife – the kids’ mum.

Back home, I called Trish’s mother, my ex-wife Carol.

‘I think he’s killed her,’ I said.

‘Ian’s not like that – he wouldn’t,’ Carol said.

While I desperately hoped I was wrong, I just couldn’t shake the awful gut feeling.

Trish loved her kids fiercely. She’d never leave them willingly.

A fortnight later, the police found blood spots on Trish and Ian’s bedroom wall, which he couldn’t explain. I knew I had to stay in Ian’s good books to get access to my grandkids. But I wasn’t allowed to mention Trish in their presence. ‘It’ll just upset them,’ Ian said.

He was trying to obliterate my daughter’s memory. I felt like strangling him.

Instead, I played detective, feeding Ian garbage stories to see how he’d react.

‘The cops are searching a swamp,’ I’d fib, watching

Ian carefully to see if any emotion would flit across his face. He never gave anything away.

Then, about five weeks after Trish went missing, Ian stopped answering my calls.

Now, I’d lost my daughter and my grandkids.

Over the years, I refused to give up hope and never stopped looking for my girl.

I put up missing person posters and dropped leaflets into mailboxes. It’d been six years since I last saw my beautiful Trish when Ian sold their family home. Before she’d vanished, they’d been redoing their laundry floor. Could she be buried underneath? I wondered.

Sadly, before we could get any answers, Carol died in 2011 of leukaemia.

Two years later, after doing scans to detect disturbed earth under the laundry, the police discovered nothing.

Then, in August 2016, a detective came to see me.

While building a wall, the new owner of Trish and Ian’s home had discovered human bones wrapped in a kids’ paddling pool liner. It was my Trish. She’d been buried in the backyard, behind the shed. The little flame of hope I’d held onto for 15 years flickered out.

A few days later, Ian was charged with her murder and interfering with a corpse.

This February, Edmund Ian Riggs, 60, appeared at Brisbane Supreme Court and pleaded not guilty to the charge of murder.

He did admit to interfering with my beautiful daughter’s corpse though, confessing that he’d moved her body.

Riggs told the court that he and Trish had been arguing in their bedroom.

He claimed she spat in his face, and said he’d pushed her back with both hands.

After hitting her head on the bedpost, he said Trish fell to the floor and convulsed for 30 seconds or more.

Checking for a pulse, Riggs said he couldn’t find one.

‘She was dead – my brain just exploded,’ he told the court. ‘I had to get her out, out of the house. I’d killed her.’

Fearing he’d be sent to jail and the kids would be left without parents, Riggs wrapped my girl’s body in a rug, put her in the boot of his car and drove her out to the bush where he buried her.

What if she was still breathing? I fretted. What if he had buried her alive?

With no medical training and in the heat of the moment, could he have missed a faint pulse

Horrifyingly, two or three years later, Riggs said he’d seen excavators around Trish’s makeshift grave. ‘I just panicked. Oh crikey, if they find her bones...’ he explained.

So he dug up most of Trish’s skeleton, re-burying her behind the shed in the backyard of their family home.

Riggs had told his kids their mum had simply walked out on them.

When the jury found him not guilty of murder, but guilty of manslaughter, I felt as though I’d been kicked in the guts.

He was due to be sentenced this week and I’m praying for a hefty chunk of time behind bars.

Trish was a good girl. She didn’t deserve this. But I refuse to be destroyed by hate.

Now, more than anything, I want my beautiful grandkids to know that I’m here for them.

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