Thomas Riha, a 39-year-old professor of Russian history at the University of Colorado, disappeared from his Boulder home on March 15, 1969. A naturalized U.S. citizen born in Czechoslovakia with a doctorate from Harvard, Riha had taught at the University of Chicago before joining CU Boulder in 1967. Colleagues marked him as meticulous and punctual; he failed to appear for classes and police found his breakfast table set with untouched food and personal effects — shaving kit, clothing — still in the house. An open briefcase and scattered papers left the normally orderly home in disarray.

Investigators quickly focused on a woman named Galya Tannenbaum, who called herself the Colonel. Tannenbaum, who had convictions for forgery and embezzlement, sold Riha’s car and house and forged title documents transferring the property to her. Police found Riha’s passport and cyanide in her home; she was arrested for forgery and later committed to the Colorado State Hospital. Tannenbaum gave conflicting statements while institutionalized, at one point telling a fellow patient she had killed Riha and disposed of his body, and at another denying involvement; she later took her own life with cyanide in the hospital. The FBI and CIA were involved early on, there were reported sightings and a U.S. Senate Intelligence Committee hearing, but no definitive answers have emerged.

Does anyone have verifiable information about Riha’s last known movements or about Tannenbaum’s actions in Boulder around March 1969?