MEDFORD, NY - The FBI says it's caught up with a serial bank robber believed to be responsible for multiple robberies in the tri-state area.

Investigators say Luis Alomar was arrested early today in Medford, N.Y.

Police say he is wanted for at least 20 robberies, including some in Greenwich.

The FBI says Alomar used a gun in some of the robberies, and threatened to shoot the tellers if they said anything.

Fairfield police believe Alomar is also a suspect for several bank robberies in their town.