BOYNTON BEACH, Fla. (CNN) -- Florida police arrested a bank robber, who was armed with a knife... and a walker.
Investigators say surveillance video shows Russell Cooper, 78, in a Palm Beach County bank. They say he threatened a bank employee with a small knife and demanded cash.
Police, meanwhile, were waiting for him outside after the robbery.
Authorities say officers used a stun gun on cooper when he refused to drop the knife.
He was arrested and charged with armed bank robbery, and kidnapping.
