Rockford Police investigate an armed robbery this morning at Stone's Hallmark, 2508 South Alpine Road. Police say a suspect armed with a knife robbed the business shortly before 10 o'clock this morning. The suspect is described as a white man in his mid 20's, 5'8, average build, and short light brown hair. Police say he was wearing a gray sweatshirt with a Seattle Seahawks logo on the front. No one was hurt during the robbery.