GAYLORD, Mich. (AP) — Police say several arrests have been made following May raids at eight medical marijuana dispensaries in Michigan’s northern Lower Peninsula.

Detective Lt. Ken Mills, unit commander of Straits Area Narcotics Enforcement, tells the Petoskey News-Review that arrests of several medical marijuana dispensary employees took place this month and more arrests are planned on marijuana-related charges.

In May, police raided eight dispensaries and searched several homes in Otsego County. Investigators say they were operating illegally.

Since the raids, Michigan State Police tell WPBN-TV they have been keeping an eye on the targeted operations. They say illegal activity has been curbed.

Michigan bans marijuana use and possession unless it’s medical marijuana, but there are restrictions on the distribution of medical marijuana.