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FORT WORTH (CBSDFW.COM) - Police in Fort Worth are looking for a suspect who is responsible for at least two store robberies. He acts like a customer, officials said. But once he is near the cash register, the crook strikes.

The first incident was at a Family Dollar location along Sycamore School Road. Surveillance video from the store shows the man wearing sunglasses and a hat, trying to blend in as an ordinary customer. Investigators said that he browsed in the aisles and even brought some items up to the front as if he was about to pay for those things.

However, when he gets to the front of the line, the suspect puts his hand up like he has a gun and demands cash.

"He took some purchases to the counter," stated Det. Brian Raynsford with the Fort Worth Police Department. "At that point, he indicated to the clerk that he had a weapon, and made a demand for cash."

The second target was a Michael's store located along Overton Drive, robbed just a few days later. While his clothes had changed -- glasses and a red hoodie -- the suspect's tactics were the same. But when the cashier called the manager, the suspect got scared and ran off.

"He is waiting for witnesses to leave," Raynsford said. "That indicates a certain level of sophistication."

The store has posted flyers, telling their customers to be on the lookout for this man. "Watch who's behind me, keep an eye on what's going on and, if you see something, just call the police," customer Erica Swancy said.

Investigators believe that the suspect is dangerous, and fear that he will strike again soon. "The way he's conducting his offenses indicates to us that he's not showing any fear of being apprehended," said Raynsford. "He's coming in the store when the store is still open. He's trying to mingle in like a regular paying customer."

Officials have not ruled out the possibility that this same suspect could be responsible for other robberies. Anyone with information about the man is urged to contact the Fort Worth Police Department. Raynsford added, "We would like to get him off the street before he hurts someone."