Two men were charged Thursday afternoon with the early-morning armed robbery of a Main Street convenience store, the second time the store has been held up in less than a month.

Roommates Christopher Grayson, 21, and Andrew Schirmann, 25, of 785 Post Road East, Unit 1B, both were charged in connection with the heist at the Merritt Country Store, 337 Main St., just before 1 a.m. Thursday.

Police said Grayson was the holdup man and Schirmann was the accomplice who drove them from the scene. Grayson was charged with first-degree robbery and sixth-degree larceny, and Schirmann was charged with conspiracy to commit first-degree robbery and conspiracy to commit sixth-degree larceny. A later charge of having weapons in a motor vehicle was lodged against the men.

Bond for both men was set at $100,000 and they face arraignment in Norwalk Superior Court.

The store was robbed by a man -- identified by police as Grayson -- who threatened the clerk with a black semi-automatic handgun, demanded money and fled on foot with cash totaling about $100 in small bills, according to police.

The robber ran in a southwest direction, police said. A Westport K-9 unit was brought to the scene and the dog tracked the suspect west along Canal to Gilder Lane, where the trail was lost.

The gunman apparently was met by the accomplice -- Schirmann, according to police -- in a car a short distance from the store and they drove from the area.

On Sept. 29, the store also had been robbed in the early-morning hours by a masked gunman who, after threatening the clerk, fled with cash receipts on foot. No one has been charged in connection with that incident.

Police Capt. Sam Arciola said investigators continue to study whether the two robberies are related.

"We are looking at the similarities between the two robberies and if they are linked," he said.

The men were identified by images from the store's surveillance camera, police said. After the suspects were identified, Westport police detectives, assisted by Bridgeport police and the Connecticut Violent Fugitive Taskforce, descended on several sites in Westport and surrounding communities where Grayson was known to frequent, police said.

Based on interviews at those locations, officers were dispatched to the rooming house at 785 Post Road East, where Grayson and Schirmann were taken into custody without incident, police said.