Heroin, crack found at Rothbury Rest Area. #OceanaCountyCrime GRANT TOWNSHIP — An arrest warrant is pending for a 25-year-old Pentwater woman who was found in possession of what is believed to be crack cocaine and heroin Tuesday, July 18, at 3:50 a.m. at the Rothbury Rest Area on northbound US 31, according to Oceana County Sheriff Craig Mast. The rest…