Conyers police are looking for a man who pulled a knife on a Walgreens cashier early Thursday morning, robbing the register of all its $20 and $10 bills at the store's Milstead location. The suspect has been identified as Mark Prentice Batiste. According to Conyers police reports, around 5:11 a.m., the cashier observed a male walk into the store covered in a cut out mattress sheet.