“It’s a very dog-friendly neighborhood, most of San Diego’s very dog-friendly,” says North Park dog owner Chris Witte. Witte brings it up because some North Park residents are concerned someone is trying to poison their dogs and they say the problem has been going on for more than a year.

Witte says he was stunned when he found out someone might be leaving poison on the street for dogs to eat. ”You’re kind of stunned, that’s the initial reaction,” he tells NBC 7.

On Tuesday, an elderly dog named Brownie was on a walk with her foster mom. “Brownie kind of lingered in an area a little too long, and she [the foster mom] realized she picked something up kind of munched on it,” Laura Oliver, the president of Lionel’s Legacy Senior Dog Rescue, says.

After eating the greenish balled up piece of meat, Brownie was rushed to the vet. “They did confirm by looking at it they believed it was rat poison," Oliver says.

For now, Brownie is OK, but Witte and other neighbors say this isn’t the first time something like this has happened. “It was in June, there was another one,” Witte says.

The San Diego Humane Society has opened an investigation into the claims.

And it isn’t just dangerous for dogs – other pets, wildlife and even children could fall prey to potential poisonings.

“We also don’t want to make accusations,” Witte says. “We don’t want to be chasing anyone down, we just want to find out why and how and what.”

Oliver offered tips for keeping your dog safe from eating anything suspect on the ground. "With an extendable leash, you might not have as much control with your pet. If they come across it, they could ingest more than maybe what Brownie did," she suggests. "I would also recommend maybe not using your cell phone when you're walking with your pet. Just enjoy and that way you're really paying attention as you see things and come across them."

The San Diego Humane Society encourages anyone who knows anything about potential poisonings in the area to reach out to them.