When his mother's friend dropped by to check on the single mum, who had not been returning text messages, Aron answered the door.
"There was a big man last night and he bashed Mummy with a bat," the little boy said. "Mummy won't wake up to give me any breakfast."
They are words that will forever haunt the Siermans family. That this innocent child most likely watched his mother die a brutal death at the hands of a relative stranger is a horror too awful to contemplate.
Single mum Sharon met her murderer on an online dating site, not realising he was a career criminal with more than 100 convictions to his name, most recently the brutal knife-point rape of a 52-year-old woman.
In the early hours of an April morning last year, he broke into her Ballarat home and attempted to rape her. When she fought back, he brutally bashed her with a cricket bat, then slit her throat and left her to die, all while her terrified son Aron hid nearby.
Dinsley was convicted of Sharon's murder last December.
Meanwhile, Aron has been left to live with his grandparents, John and Denise, who have shared their heartbreak in the February issue of The Australian Women's Weekly.
"Never, ever, go on to a dating website," warns Sharon's mum, Denise. "You just don't know who you're talking to. I wish all of them were shut down so no family ever has to go through what we're going through.
"We're just a normal Australian family, but with the click of a button, she made the wrong choice. If this can happen to us, it can happen to anyone."
The Ballarat community is holding a fundraiser for Aron on February 22. Details are available at www.facebook.com/AronSiermanFundraiser.