A Muslim convert who talked about his desire to wage "acts of violent jihad" was charged in a plot to set off hand grenades at a shopping mall at the height of the Christmas rush, authorities said. Derrick Shareef is in custody accused of trying to trade two stereo speakers for a 9 mm pistol and hand grenades authorities said. The FBI said it was tipped by an acquaintance of Shareef, then recorded the 22-year-old planning to use hand grenades to blow garbage cans into clouds of flying shrapnel in a crowded mall the Friday before Christmas. Authorities said he was arrested Wednesday when he tried to make the trade with an undercover agent in a Rockford, Illinois, parking lot. Shareef was charged Friday with crimes that could send him to prison for the rest of his life, and was ordered held without bail.