Published: Mar 19, 2013 12:22 PM EDT

NORTH FORT MYERS, Fla.- Lee County Sheriff's deputies are looking for the suspect accused of robbing the Twisty Treat on Pine Island Rd. Monday night.

The owner told officers he was getting ready to close the business, when a suspect in his 20s made entry through an open side door. The suspect allegedly punched the victim in the face, knocking him to the ground. The victim said the suspect told him he would be shot if he got up. That's when the victim said the suspect took all the cash from the register and ran from the building.

A customer witnessed the suspect run past him, toward Beachwood Dr. The witness tried to follow him in his company tow truck, but lost site of him. He called 911 at that time. An air unit and K9 were called to assist.

Neither the victim nor the witness saw a weapon. The witness told deputies the suspect was wearing dark-colored shirt, jeans and carrying a backpack.

The investigation continues.