EDISON - FBI agents are asking for the public's help as they look for a serial bank robber believed to have struck at least six banks in four different counties.

The robberies go back about 10 months, but the most recent was on Saturday in Cranford. Video shows the robber approaching a teller at Garden State Community Bank on North Avenue. He pulls a gun and demands money be placed in a black bag, before walking out as calmly as he came in.

The FBI says the robber is brazen and very good at what he does. "He seems very controlled," says Public Affairs Officer Barbara Woodruff. "He knows what he is doing, not anxious or nervous."

The robber also struck the same bank in Newark twice, as well as Iselin, Clark, Edison and Watchung.

Investigators say the suspect often dresses the same in the robberies, wearing a dark-colored shirt and a black baseball cap.

The FBI believes the suspect is armed and dangerous, and anyone who recognizes him should call police.