WASHINGTON (AP) — The Food and Drug Administration is trying to solve a stubborn mystery surrounding the deaths of almost 600 dogs that ate jerky treats, and officials are hoping pet owners and veterinarians can help them figure out what exactly may be causing the illnesses.

The problem appears to be tied to dog pet treats made in China, the FDA said, though investigators haven’t yet found a certain cause. The FDA says it has received reports of illnesses in 3,600 dogs and 10 cats in the United States since 2007, and 580 dogs died. The pet treats were sold under a wide variety of brand names.