It was not just that a bank in Fairfax County was robbed Friday. It was that it appeared to authorities that the robbery might have been the sixth by the same man at the same bank.

Six robberies at the same suburban bank branch in three years appears relatively unusual, and six by the same man even more uncommon.

Friday’s robbery occurred at the TD Bank branch in the 6600 block of Richmond Highway, in the Alexandria section of Fairfax County.

“Police have reason to believe that this bank robbery may be related to previous robberies at the same bank,” county police said Friday in a statement.

Police noted an FBI statement asserting that the Sept. 9 robbery at the branch was believed to have been the fifth there by the same man.

Because the branch is near Beacon Hill Road, the robber has been dubbed the “Beacon Hill Bandit.”

In the five previous robberies, which began in March 2010, the FBI said, the robber used a similar technique.

He made either a spoken or written demand for money, the FBI said. The written demand has come in the form of a note passed to tellers. The man has provided his own bag, according to the FBI.

In three of the robberies, the FBI said, the man implied that he had a weapon.

In reporting Friday’s robbery, county police said it occurred around 12:30 p.m.

They said the man entered and demanded money. A teller complied, police said, and the robber fled with an undisclosed amount of cash.

Three surveillance camera photos were released by county police.

The man in the pictures from Friday was wearing a baseball-style cap and in one picture had a plastic bag in his left hand.

In the pictures from the previous robberies, the robber wore a hat of some sort. In two of them, he wore a baseball-style cap, and in two he wore a construction-style hard hat.

In Friday’s robbery, the person was wearing glasses. In the earlier robberies, the FBI said the robber was wearing sunglasses.

For the same robber to take money from the same bank branch six times appears relatively uncommon. A survey of recent news reports shows little to match it.

A report published in the Los Angeles Times in 2007 said a man was thought by authorities in Southern California to have robbed the same bank in Huntington Beach five times.

The account said the man would pass tellers a note saying he had a bomb and a gun.

However, it said, he was apparently unarmed. In one incident, it said, the robber pedaled away on a mountain bike.