Michigan police are looking for a person who spread “large quantities of broken glass” across a popular beach.

The glass was discovered Tuesday at Sleeping Bear Dunes National Lakeshore on Lake Michigan. A majority of it was distributed around the Good Harbor picnic area, Ranger Andy Blake says. “The glass was not dumped in one spot, but is spread fairly uniformly up and down the beach for several hundred yards,” he says. “It is definitely a hazard to beachgoers as it consists of literally thousands of freshly broken pieces mostly one half to two inches in size.”

Surprisingly, it isn’t the first time someone committed the malicious act on a Lake Michigan beach. In 2017, broken glass was found on the sand near the Lane Road parking area.