There have been four incidents in the past three days.
Police say the suspect covers his face and puts his hand under his shirt, pretending to have a gun.
The suspect is described as a white male, approximately 35 to 40 years old, standing about 5-foot-7 to 6-feet tall and weighing about 200 pounds. He's been seen wearing dark glasses and a baseball cap.
So far, he's targeted stores and banks in Midtown and Lower Manhattan. Police say once he enters the location, he covers his face with one hand and places his other hand under his shirt, simulating a gun.
He usually approaches an employee at the counter and demands cash. Police ask anyone with information to call Crime Stoppers at 800-577-TIPS.