NEW : The family does n't know why Sutyagin is being sent to Britain . Bail hearing set for Thursday for one suspect in Russian spy case . NEW : Arraignment of all one suspects in the United States set for the United States federal court on Thursday . Scientist in Russian jail relays plans for exchange to mother , brother . Ernst Chyorny had to sign a letter admitting guilt , his brother tells the Russian Federal Security Service .
NEW : Bail hearing set for Thursday for one suspect in Russian spy case . NEW : Arraignment of all one suspects in the United States set for the United States federal court on Thursday . Scientist in Russian jail relays plans for exchange to mother , brother . Ernst Chyorny had to sign a letter admitting guilt , his brother tells the Russian Federal Security Service .