NEW : Preliminary hearing set for Friday for a suspect in Russian spy ring . NEW : Trial of all 10 suspects in the United States set for New York federal court on Thursday . Dean Boyd , spokesman for the National Security Division at the U.S. Department of Justice , also had no comment on the case . Scientist in Russian jail relays plans for trial to mother , brother . Igor has had to sign a letter admitting guilt , his brother tells CNN .
NEW : Preliminary hearing set for Friday for a suspect in Russian spy ring . NEW : Trial of all 10 suspects in the United States set for New York federal court on Thursday . Scientist in Russian jail relays plans for trial to mother , brother . Igor has had to sign a letter admitting guilt , his brother tells CNN .