The couple , Wayne Guay , 57 , a former employee of the city 's Sanitation Department , and Dianne Guay , 55 , a former employee of the city 's Department of Education , were believed to have left their home in Myrtle Beach , S.C. , about 4 a.m. on Thursday in a four-door , white Mazda sedan with a South Carolina license plate , '' 732-RZZ , '' according to the Horry County Police Department .