Perseus was the codename of a possible Soviet spy alleged to have breached U.S. national security at Los Alamos during the Manhattan project. This name is also given to a spy at White Sands Missile Range, located further south near Las Cruces, New Mexico. Evidence for his or her existence is based on a few references in KGB archives opened (and later closed) to researchers in the early 1990s, after the fall of the Soviet Union. There are also a few references to Perseus in the VENONA decrypts as PERS. The identity of this person, or even whether or not they actually existed, is unknown, and many of the facts in the matter are questionable.