"Oh, look at that... We're rich... We're rich!"―Roscoe[src]
Roscoe was a member of the grave robbing gang led by Fedora, which recovered the Cross of Coronado in 1912. After Indiana Jones stole the Cross, Roscoe chased Indy and fought him on the circus train. During the fight, Roscoe gained an edge over Indy by pulling a knife, but lost his opportunity when he was nearly gored through the train car by an agitated rhinoceros. After Indy was pulled to safety from the lion car, Roscoe stepped in to grab the Cross but let go because he was afraid of a snake wriggling out of Indy's sleeve.