 He gives them a drug that will knock Vautrin unconscious, so they can search on his shoulders for the branded letters T.F., which stand for "Travaux [forcés]" and "Faussaire" ("hard labor" and "forger").The plan works and Collin is arrested and imprisoned in Rochefort.Later, it is revealed that Collin escapes prison disguised as a guard escorting another prisoner.