PORTLAND, Ore. -- A $10,000 reward is being offered for information leading to the arrest and conviction of a man the FBI calls the "Waddling Bandit."

Investigators believe the man has robbed as many as 20 banks in the past two years. They nicknamed him the "Waddling Bandit" because of the way he walks.

The banks he is suspected of robbing stretch from Kelso, Wash., to Medford in southern Oregon.

FBI officials said he has never shown a weapon, and that he has worn a hat in all of the robberies.

In about half of the robberies, he targets bank branches inside grocery stores.

Authorities said the man may also be diabetic and may have a gambling habit.

The man is described as white, in his 50s, 5 feet 10 inches tall and between 200 to 250 pounds. He has a heavy build and has dark or gray hair, authorities said.

Anyone with information on his identity is asked to call 503-224-4181. In Salem, call 503-362-6601.