CHICAGO (WBBM NEWSRADIO) — Campaign dirty tricks are being reported in DuPage County in the race for the GOP nomination for Sheriff.

“Out in DuPage, signs are a big part of the game,” said James Mendrick, the DuPage County Sheriff’s Patrol Commander looking to replace out-going Sheriff John Zaruba.

READ MORE: Obamas Make Surprise Visit To Comer Children's Hospital For Holiday Celebration

Mendrick had a billboard put up at Route 83 and Irving Park Road in Bensenville, and he said, sometime Monday night, someone climbed 50 feet and vandalized it. He said Bensenville police are investigating.

James Mendrick, campaign billboard vandalized in Bensenville (James Mendrick)

Mendrick suspects someone who supports his opponent, Undersheriff Frank Bibbiano, is behind the vandalism.

READ MORE: Three Men Shot Outside Garfield Red Line Station

“I can’t explain why or who. I would hope my opponent isn’t involved in this in any way. Maybe this is just people supporting him. I really don’t know,” he said.

Mendrick also said at least 150 of his campaign signs have also been stolen or damaged. Sometimes, he said, signs for his opponent find their way to the same location afterwards.

Mendrick said the vandalism seems like a coordinated effort.

“It actually does kind of seem like it. The weird thing is it’s intensified over the last week and a half or so, after I got the Daily Herald endorsement,” he said.

MORE NEWS: Some Parents Not Pleased As Kids Are Required To Wear Masks During Outdoor Recess At Jonathan Burr Elementary School In Wicker Park

WBBM Newsradio has asked the Bibbiano campaign if it had any comment.