A Yarloop pet owner is warning other local residents to guard their pets after her third dog died from suspected poisoned baits in as many years.

Danielle Gratton-Wilson, whose dogs were companions for her two children – one with autism and another with a learning disability – found her American Staffordshire terrier poisoned on Saturday morning.

Dylan Gratton-Wilson with Hercules, the family pet who died from a suspected poison bait.

He died not long after and Ms Gratton-Wilson said the family of four were devastated.

"This is the third dog of mine dead in three years, and I have another dog that I now have to re-home," she said.