In 2026, a conspiracy theory emerged alleging that the deaths or disappearances of several people, some described online as scientists tied to classified or sensitive research, were connected to secret knowledge about UFOs, advanced energy projects, materials science, or related subjects. Speculation started spreading through social media following the February 2026 disappearance of retired U.S. Air Force Major General William Neil McCasland. It then began drawing wider media attention and comment from U.S. federal officials, including the FBI and Donald Trump. Cases cited by proponents span several years and involve unrelated circumstances, including natural death, homicide, suicide, and missing-person reports.