Omaha police are investigating a robbery that was reported early Sunday morning.According to officials, police responded to reports of a robbery at Walgreens near 30th and Dodge streets around 2:10 a.m. Sunday.Employees told officers that a black male wearing a red stocking cap entered the store, showed a gun and demanded money, according to authorities.After taking cash, the suspect fled on foot and was seen traveling east, police said.Anyone with information is urged to contact Omaha Crime Stoppers at 402-444-STOP or go to www.omahacrimestoppers.org.