This bank robber's calling card reflects his inability to spell.

Federal authorities are searching for a man they've dubbed the "Spelling Bee Bandit," who is believed to have struck four banks in Eastern Massachusetts over the past few weeks.

Each time, he slides the teller a note written on the back of a withdrawl slip with a single word: "Robery." Each time it is misspelled.

Caught on surveillance video, the man is seen wearing wraparound sunglasses and a baseball hat or hooded sweatshirt. Over the past two weeks, he is believed to have robbed banks in Arlington, Reading, Burlington and most recently in Peabody, according to the FBI. All the banks are within about 20 miles north of Boston. He seems to prefer TD Bank, where three of the four robberies have taken place.

While he has never flashed a weapon, officials say the suspect has become increasingly aggressive.

The suspect is described as in his late 30s or early 40s with dark hair, and a slim build. He is around 5-foot-11 to 6-foot-2 inches tall and weighs about 160 pounds.

At the time of a Nov. 13 robbery at the TD Bank, he was wearing jeans, a dark jacket, dark sneakers with white soles, sunglasses and a white New England Patriots hat. Witnesses told the FBI that he has short hair, a thin face, a beard.

The FBI wouldn't say how much money he has stolen. It is offering a reward of up to $1,000 for information that could identify him and lead to his arrest.

Anyone with information should call the FBI Boston Division's Violent Crimes Task Force at 857-386-2000.