Police are trying to determine what would lead an individual to leave thousands of thumbtacks strewn about a Northern California dog park, prompting them to begin patrolling the area and consider setting up security cameras to get down to the bottom of the bizarre act.
Dog owners became aware of the dangerous tacks at the Ohlone Dog Park in Hercules last month and collected enough to fill several sandwich bags, ABC's Bay Area affiliate KGO-TV reported. But when they returned, more tacks had appeared.
"After we've gotten most of them out, then we come back and they're back again," dog owner Annie Miller said.
The incidents have continued since then, with the thumbtacks being found in a nearby creek and even in waterbowls. At least two dogs have been injured, and even though the damage wasn't permanent, it did cost their owners hundreds of dollars in veterinary bills, according to NBC Bay Area.
"One of the guys was picking them up and his dog swallowed one and he had to take him to the vet," Miller said. "I'm sure it's not a very nice vet bill."
"Another person, their dog was limping and she put the paw up and there was a tack, not all the way in, but it was in the paw," dog owner Kathy Long said.
Police noted that the thumbtacks also leave children at risk since they're small enough to swallow.
"A child is very quick with that kind of thing and could have it in his mouth and swallow it before any parent could reach them," said Connie Van Putten, public information officer for the Hercules Police Department.
Police don't know what the motive behind the thumbtacks is, but they have posted notices alerting people to be cautious, according to CBS News, and urged anyone who may have information about the case to call Hercules police at (510) 799-8260.