Jack Webb would go on to produce, write & direct a 1970s series called "U.F.O." which was about two U.S. Air Force guys going around investigating U.F.O. sightings.
It was done basically the same as "Dragnet" except they were looking for possible alien invaders, not criminals. Near the end of every episode, the two guys would find evidence that the sighting was either a hoax or case of mistaken identity, then at the very end, after the case was closed, someone would find evidence it had been genuine, but either lost the evidence or never told anyone.