For 22 years, from 1979 until his arrest in 2001, FBI agent Robert Phillip Hanssen sold government information to the Soviet Union and later the Russian Federation in exchange for cash and diamonds, totaling over $1.4 million. His standard method of conveying information to the Russians was to “dead drop” documents or disks beneath a footbridge near his home.

To indicate the dead drop was ready for pickup, Hanssen would attach a piece of tape to the entrance sign of the park. It was inconspicuous enough that anyone who wasn’t looking for it probably wouldn’t notice.

For many years, Hanssen worked within the FBI’s Soviet Analytical Unit, the department responsible for capturing Soviet spies in the United States. He used his placement in this unit to report back to the Soviet Union the names of KGB agents who had defected or were acting as double agents. Hanssen also informed the Russians of a secret tunnel the FBI had dug under the Soviet embassy in Washington, D.C. Despite all this, the Russians only knew him by his codename, “Ramon Garcia.”

At one point, Hanssen and his team were assigned with investigating Hanssen’s own espionage. The investigation concluded that another FBI agent was leaking information, and Hanssen’s activities went on. Another time, Hanssen was able to warn Russia of an ongoing investigation, and as a result the FBI was unable to prove any spying.

After the fall of the Soviet Union, Hanssen refrained from selling information to the Russians, but resumed again in 1999, unaware that an FBI-CIA investigation was circling closer to him. In exchange for witness protection in the United States, a former KGB agent stole the relevant files from Russia and U.S. intelligence agencies were able to identify Hanssen as the source of the leaks.

Finally on February 18, 2001, Hanssen was arrested while hiding a bag stuffed with documents under the bridge in Foxstone Park, near his home. He pleaded guilty to 15 counts of espionage. Although suspicions were raised on occasion about Hanssen in the FBI, he was seen by most as a caring father and devout Catholic who frequently disparaged the “godless” Russians. The Department of Justice deemed Hanssen’s espionage and the length he went undetected as “possibly the worst intelligence disaster in U.S. history” at that point in time.

If you go to Foxstone Park today you can still see the bridge where Hanssen funneled covert information to the Soviet Union.