In the mid-'80s, he and his wife again appeared on the FBI's radar screen, when they approached the Albuquerque field office and volunteered to inform on visiting delegations from the People's Republic and on Chinese scientists in the U.S. The FBI dropped the Lees from its rolls in 1991.
There is a second advantage to using lasers in preference to radar: while they have a similar range, laser sensors have a significantly wider field of vision.