In prosecution on wire and mail fraud charges arising out of defendant’s scheme to sell stolen merchandise provided to him by group of individuals described as “gypsies,” Dist. Ct. did not commit plain error in admitting testimony from govt. witnesses that described said “gypsies” as inveterate thieves. While defendant argues that said testimony violated Rules 401 and 403, record showed that defendant also used “gypsy” term in recorded statement when describing individuals with whom he had done business, and govt. witnesses gave specific reasons (including fact that merchandise provided by said individuals often contained store and security tags) why they believed that defendant knew that said individuals provided him with stolen merchandise. Ct. also found that prosecutor’s single reference in opening argument to fact that FBI agents had obtained warrant prior to conducting search of defendant’s warehouse did not deprive defendant of fair trial.