The man police say robbed the Stop & Shop in Reading in June may have had some practice over the past few weeks. 

Police believe the same man may have robbed banks in North Andover, Chelmsford and Salem, N.H., recently.

The suspect walked into the Citizens Bank at Stop & Shop in North Andover Saturday at about 4:30 p.m. and demanded the tellers give him money, saying he had explosives in the bank. One teller told him to take off his sunglasses and the man fled without getting any cash. Police and fire crews did a sweep of the store and made sure there were no explosives, and the building was reopened for business within an hour.

On July 2, there was a similar incident in Salem, N.H., when a man walked into the Citizens Bank at Shaw's on South Broadway that afternoon and handed the teller a note saying he had a bomb and a hostage and demanding money.

Police described that suspect as a white male between 25 to 35 years old, wearing a black shirt, glasses and a hat. And in surveillance photos, the man resembles the suspect in this past weekend's North Andover robbery.

And this past Thursday, a man matching that description -- and looking like the man in the other cases -- reportedly robbed the Citizens Bank at Stop & Shop on Chelmsford Street in Chelmsford.

That man passed a note to a teller demanding money, police said, and he fled with an undetermined amount of cash in a newer model vehicle, possibly a Nissan Altima or similar, gray or gold.

Police suspect the same man may have committed the robberies in all of these cases. Not only do the surveillance photos all look like the same person, but each robbery has had similar methods of operation.