Mississippi man linked to ricin letters to Obama pleads not guilty TUPELO, Mississippi (Reuters) - A Mississippi martial arts instructor has pleaded not guilty to charges he sent ricin-laced letters to President Barack Obama and two other public officials. James Everett Dutschke, 41, who was arrested on April 27, pleaded not guilty to all five counts of a grand jury indictment, court records filed on Tuesday showed. His trial has been set for July 29 and Dutschke faces a maximum penalty of life in prison for threatening the president and others by mail and "possessing a biological agent, toxin and delivery system for use as a weapon." The indictment against Dutschke was filed last Friday as authorities, in separate cases in Washington state and Texas, were investigating two other batches of ricin-contaminated letters sent to Obama. The grand jury indictment includes one count charging Dutschke with having made it appear that another man, Paul Kevin Curtis, had mailed the letters to Obama, a U.S. senator and a Mississippi judge. Dutschke has been held without bail since his arrest. He waived his right to appear at an arraignment set for Thursday in court filing on Tuesday. Reporting by Tom Brown; Editing by Lisa Shumaker