The robbery attempt took place at about 6 a.m. on April 9 inside the Sputnik coffee shop in the 2000-block of West 51st Street on the Southwest Side, police said.
Surveillance video shows a man in a blue jacket with a gun at his side. Police said the man demanded money and when the cashier refused, the robber grabbed the register and ran out the door.
The store owner ran after the robber and got the register back.
Anyone with information on the robbery is asked to contact Detective Toner at 312-747-8227 or Area Central HQ at 312-747-8380.