Someone is putting poison in hot dogs and poisoning dogs in the Eau Claire area, and authorities in western Wisconsin are trying to find the perpetrator.

Police in Lake Hallie, just northeast of Eau Claire, said in a statement that they have “received numerous calls regarding someone putting an unknown substance” in cutup hot dogs, wrapping them in dental floss and throwing them in residential yards.

“Dogs have eaten them and become sick,” the statement went on to say. “If you happen to see more of this type of activity, please do not let your animals ingest it and report it immediately.”

Trail cameras have recorded blurry images of a “suspicious subject” in the area, the statement continued.

Police have yet to reveal what type of poison has been used. No fatalities among the dogs have been reported.

Anyone with information about these incidents is urged to contact police at 1-715-726-2666.