In 1999, a U.S. Army World War II veteran applied for his Social Security pension. There would have been nothing out of the ordinary for any other vet down on his luck. He knew that any veteran of WWII was able to apply at the Social Security office for special benefits for Army vets during that war. Later that year, 1999, he received a notification by mail, with just one line:
"We are writing to tell you that you do not qualify for retirement benefits."
The veteran applying for that bit of extra cash every month applied from the U.S. Embassy in Moscow. His name was George Koval, and just 50 years prior, he was giving the Soviet Union the information it needed (and couldn't produce itself) to build an atomic bomb.
The American-born Koval actually moved to Russia in his early years with his family. It was there he was recruited by Soviet intelligence to return to the United States and work as a spy. He came back to the mainland U.S. by way of San Fransisco, moved to New York, and became an electrical engineer for a company subcontracting to General Electric. Except this company was a front company owned by Soviet spies. Koval soon became the head of his own GRU-led cell.
Then, he was drafted to fight in World War II. But instead of fighting in the Infantry, he was sent to the City Colleges of New York to study more and prepare for his real assignment – the Manhattan Project.
Koval was transferred to Oak Ridge, Tenn. where he became the projects public safety officer. He had unfettered access to everything in the Manhattan Project, especially the radioactive elements necessary to trigger the fission that would create the world's largest explosions. He sent everything back to the Soviet Union, including production processes for plutonium, uranium, and polonium. The coup de gras, however, was the polonium initiators that triggered the fission reaction. The Soviets got those designs too.
Agent DELMAR, Kovals code name, was given unrestricted access to all the top sites of the Project. He freely walked around the halls of the Dayton, Ohio facility where polonium triggers were manufactured. He had free access to the Los Alamos National Laboratory where the triggers were integrated into the greater design. Koval was basically able to guide Soviet scientists through the process, step-by-step. He sent information back to the Soviets for three years, between 1943 and 1946.
Eventually, the heat started getting to Koval, so he decided to apply for a passport. He told friends and colleagues he was going to Europe or Israel, but he left one day and never returned. Koval escaped to the USSR, where he was discharged from the Soviet military as an unskilled rifleman and given the appropriate pension... which probably wasn't much. That's likely the first step in what led him to apply for special benefits at the U.S. Embassy in Moscow that day in 1999. The United States never suspected his involvement until the mid-1950s. By 1999, he was an FBI legend.
Koval lived until 2006 when President Vladimir Putin posthumously declared him a Hero of Russia for being the only spy to ever get into the Manhattan Project – much too late to get that pension.