The bank robber was an escaped convict.
The bank robber was a Caucasian male with short black hair. Part of the light brown shirt he was wearing could be seen when he was unmasked.
He didn't have much characterization beyond a determination not to go back to prison; he was silent when caught.
He was a notorious bank robber who was eventually caught and sent to prison.
The Scooby-Doo Show
When he broke out of prison, he got involved with Captain Clemens, who was helping escaped convicts evade the police by giving them makeovers and phony papers so they could get out of the country. He disguised himself as a sea creature known as the Creepy Heap from the Deep to scare people away from the operation.