Dover Police are investigating an armed robbery at the Fulton Street Deli at 316 Fulton St. Dover. Police spokesman Capt. Tim Stump said a black man came into the store July 11 and demanded money, threatening employees with a knife. The man fled after being given an undetermined sum of cash. He was described as being between the ages of 45 and 55, heavyset, and wearing a yellow pullover sweatshirt and a red baseball cap. Anyone with information on this crime is asked to contact the Dover Police Department at (302) 736-7111.Callers may remain anonymous. Tips also may be submitted to law enforcement through tip lines maintained by Delaware Crime Stoppers at (800) TIP-3333 or online at www.tipsubmit.com.