On March 20, 1966, Dexter Township resident Frank Mannor claimed to have investigated a UFO that landed in a swamp near his house. Over the next few weeks, police received hundreds of accounts of mysterious lights, prompting a Michigan congressman to ask the Air Force to investigate. One possible explanation offered by a U-M professor was swamp gas, a natural phenomenon in which clouds from rotting vegetation undergo chemical reactions that result in flickering, dancing light. The lead Air Force investigator proposed the swamp gas theory at a press conference, resulting in journalistic uproar. One national newspaper headlined the story “Air Force Insults Public with Swamp Gas Theory.” As sightings waned, so did public interest. However, the mystery remains.
— Adapted from “Ann Arbor vs. the flying saucers” by Alan Glenn, Michigan Today