 Ultimately, Yoshimura was convicted on explosives and weapons charges and sent to state prison for six months; she was paroled in 1980.In 1991 Yoshimura was granted limited immunity to testify during a grand jury investigation into the fatal 1975 bank robbery, which killed Myrna Opsahl, 42-year-old mother of four.One SLA member, Michael Bortin, had pleaded guilty for the robbery itself.