Thomas Riha

• Missing Since 03/15/1969
• Missing From Boulder, Colorado
• Classification Endangered Missing
• Sex Male
• Race White
• Date of Birth 04/17/1929 (97)
• Age 39 years old
• Height and Weight 5'10, 140 pounds
• Distinguishing Characteristics White male. Brown hair, blue eyes. Riha was born in Prague, Czechoslovakia; his original name was Tomáš Ondřej Karel Říha. He speaks Czech and Russian as well as English.

Details of Disappearance

Riha was last seen at a dinner party in Boulder, Colorado on March 15, 1969. He told the host he thought someone was following him. One person offered to let him stay the night, but he declined. He has never been heard from again.

He had been born in Prague, the son of a lawyer and a language teacher of Jewish descent, and survived the Nazi occupation of Czechoslovakia. After World War II he went to Britain to learn English, then moved to the U.S., enrolling in the University of California at Berkeley in 1947 to study political science. He became a naturalized U.S. citizen and went on to get his PhD in history from Harvard University. At the time of his disappearance, he was an associate professor of modern Russian history at the University of Colorado at Boulder.

Due to Riha's background, knowledge of the Russian language and travels to the Soviet Union and Czechoslovakia, there was speculation that he was involved in espionage. He traveled to the Soviet Union for an exchange program at Moscow State University in 1958, and stopped in Czechoslovakia en route, against the instructions of the program. His nephew lived in Prague at the time, and Riha stayed with him.

While he was there, according to his nephew, an agent from the Czechoslovak secret police tried to convince Riha to defect. After Riha returned to the U.S. in 1959, the FBI vetted him as a potential double agent. The CIA also later admitted they had had a "general counterintelligence interest" in him. However, both the FBI and the CIA later denied that he had ever worked for them.

The last person to see him was Galya Tannenbaum (whose real name was Gloria Ann Forest), a woman who claimed to be a colonel working in military intelligence. She claimed she had been in a relationship with Riha for several months, and that she told him she could help him get his nephew to the U.S.; the nephew had fled Czechoslovakia by this time and was in Vienna, Austria. Tannenbaum had a criminal record for forgery and embezzlement. A photo of her is posted with this case summary.

Tannenbaum claimed Riha was alive in Montreal, Quebec, Canada and was hiding from his wife, with whom he was in the process of a divorce following a four-month marriage. The CIA also claimed was "alive and well", based on claims from an FBI agent whom they refused to identify, but later said this statement had been made in error. Because of the statements that Riha was alive, the police closed the missing persons report on April 4. The investigation was reopened in September.

After Riha went missing, Tannenbaum began selling off his assets, including his house and car, and issued checks to herself in his name. She donated his $19,000 art collection to the Denver Art Museum and gave his library of 1,000 books to a college in Denver. She was subsequently charged with a misdemeanor and six felonies; four of the felony charges were for falsifying Riha's signature on documents after his disappearance.

Tannenbaum was also connected to two cyanide poisoning deaths that happened after Riha's disappearance. Riha's engraved gold wedding band, which he was wearing at the time of his disappearance, turned up at the home of one of her alleged murder victims. In 1970, Tannenbaum was declared insane and sent to the Colorado State Mental Hospital. She died there of cyanide poisoning in March 1971. Before her death, Tannenbaum denied having killed Riha and said he was in Russia.

The Senate Select Committee on Intelligence Activities questioned the CIA's former chief of counterintelligence, James J. Angleton, after Riha's disappearance. Angleton said a CIA agent had reported having met with Riha in Bratislava, Czechoslovakia in 1973. This information could not be verified, but the Senate committee concluded Riha had probably left the country for personal reasons and was alive somewhere in Eastern Europe.

In 1976, Riha's nephew, who always believed his uncle had been murdered, petitioned to have him declared legally dead so his estate could be probated. He also filed a lawsuit against the CIA to compel the agency to turn over all the information they had about Riha and his possible fate.

Journalist Eileen Welsome wrote about the case in her book Cold War Secrets: A Vanished Professor, A Suspected Killer, and Hoover’s FBI, published in 2021. Her conclusion was that Tannenbaum had murdered Riha. He has never been located and his case remains unsolved.