A federal grand jury indicted a Sacramento man Thursday on 13 charges related to a series of anthrax scares across the Unites States that turned out to be hoaxes. The indictment accuses Marc Keyser, 66, of mailing threatening packages to several media outlets, businesses and Rep. George Radanovich. It charges Keyser with 10 counts of hoax mailings and three counts of mailing threatening communications. Twelve of the charges each carry a maximum sentence of five years in prison. Mailing a threatening letter to Radanovich's office carries a possible 10-year prison term because he is a congressman. Keyser, who was arrested Oct. 29, has yet to enter a plea and remains free on $25,000 bond.