Rudy "Slippery Hands" Sable is an ex-convict who was working as a maintenance man at a Little League field in Smalltown.
He has brown hair and a black mustache, and wears a janitor-style uniform.
He seemed rules-conscious, demanding that the gang not dig up the field in their investigation because they needed a permit. (He was actually more concerned that they might find his loot).
Twenty-five years back, Sable robbed a bank in Smalltown. He was caught and sent to prison, but the loot was never found.
Scooby-Doo (DC Comics)
When he got out of jail, he found the field where he buried the loot had been renovated and he couldn't easily find the hiding place. He got a job as a maintenance man to facilitate his search, and he dressed up as the Ghost Coach to scare people away from the Little League night games so that he could search without being disturbed.