COLDWATER, Mich. (AP) — Authorities say grave markers were tipped over, broken or thrown at a cemetery in southern Michigan.

Coldwater Municipal Services Manager Dave Sattler tells The Daily Reporter that he discovered the damage on Wednesday at Oak Grove Cemetery. He estimated that more than 30 grave markers in the oldest section of the cemetery were damaged.

The vandalism is believed to have taken place between Tuesday evening and Wednesday afternoon. The cost of the damage wasn’t immediately known. Police in the community about 100 miles southwest of Detroit are seeking tips from the public in the investigation.

The same cemetery was targeted in 2007, when two teenage boys were blamed for damaging about 100 grave markers. Repairs at the time cost more than $20,000.