Edmonton police are investigating a potential case of animal cruelty after a man told them his dog became violently ill following a trip to a local off-leash area.

The pet owner also contacted CTV News, but asked for anonymity. He says his vet confirmed poisoning was the reason his dog became sick.

Signs are now posted at Edmonton's Laurier Park, warning people at least three dogs were poisoned there in the last week.

The Edmonton Police Service's West Division has not confirmed the cases, but said in a Twitter post Sunday they are looking into the allegations.

Those who took to the park this weekend say they're disturbed by the news.

"I'm very concerned," said Laurie Wiles, who was out walking her dog Karma Sunday morning. "I made sure that she was very close to me today. I didn't let her run very far away."

On top of the worry, Wiles says she's frustrated by the idea of a targeted attack.

"We can't let our dogs run just anywhere in the city and this is one place that's put aside, so you'd hope you'd be safe here."

Angela Kinney, who was out walking her 16-year-old dog Chloe, agrees.

"Very upsetting - you really wonder what sort of a person would do that," she said. "I really don't know what sort of mind would think about poisoning animals."