The scientists were all working on space and nuclear research, sparking conspiracy theories, a federal probe, and even comments from Donald Trump

At least 11 U.S. scientists linked to U.S. nuclear and space research programs have died or vanished in recent years, prompting a federal investigation into a situation President Donald Trump called “pretty serious stuff.” 

On April 20, the House Oversight Committee announced that it would look into the deaths and disappearances after committee chairman James Comer (R-Ky.) warned that “something sinister could be happening” on Fox & Friends. Comer said that at first he thought it was “some kind of crazy conspiracy theory,” but now believes it could be a national security concern. 

CNN reported that the FBI is leading efforts to find connections between the missing and deceased scientists and is working with the Department of Energy, Department of Defense, and state and local law enforcement. NASA posted on X that the agency is “coordinating and cooperating with the relevant agencies in relation to the missing scientists,” but currently sees no national security threat. 

Trump has slashed funding for science research in his second term, providing an opening for other countries to poach leading scientists. Could the missing researchers be part of a brain drain? Some GOP lawmakers seem to think so. Congressman Eric Burlison (R-Mo.) posted on X, “We are in competition with China, Russia, and Iran on nuclear technology, advanced weapons, and space. Meanwhile, our top scientists keep vanishing.”

Who are the scientists who have died or disappeared?

Questions about a possible sinister connection between the 11 deaths and disappearances began to emerge after William Neil McCasland, a 68-year-old former U.S. Air Force major general, was reported missing from his Albuquerque home by his wife on Feb. 27, 2026. McCasland left his prescription glasses, phone, and electronics behind; he is thought to have taken his .38 caliber revolver with him. Two months later, officials still can’t say where he went.

McCasland was the onetime commander of the Wright-Patterson base, central to the Roswell incident; his connection to UFO lore and classified space weapons programs fanned the flames of speculation sparked by a YouTuber named Daniel Liszt when he posted a video theorizing that a Portuguese physicist was assassinated because of his work in advanced fusion research. Nuno Gomes Loureiro, a renowned nuclear science professor, was shot and killed at his Massachusetts home in December 2025. He had recently been named director of MIT’s Plasma Science and Fusion Center.

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Liszt, who goes by the handle Dark Journalist, theorized that Loureiro’s work was “potentially so transformative, that if you get a real leg up in the research… then you become a sort of database that needs to be erased potentially.” He tied Loureiro’s murder to the deaths of other scientists who had worked in the U.S. Strategic Defense Initiative program.

Right-wing influencer Jessica Reed Kraus wrote a Substack article in February that drew parallels between Loureiro’s death and that of astrophysicist Carl Grillmair, who was shot and killed outside his rural California home. In another post, she deemed McCasland’s disappearance a “Conspiracy Alert!” The Daily Mail kicked the story into high gear in March, reporting that the “mystery of five missing scientists sends [a] chill across America.”

What ties the scientists together?

Comer and other lawmakers say that the string of mysterious deaths and disappearances began in July 2023 with the death of Michael David Hicks, a 59-year-old scientist who specialized in comet and asteroid research at NASA’s Jet Propulsion Laboratory (JPL) in California. There has also been speculation surrounding the 2022 suicide of an anti-gravity scientist named Amy Eskridge, after the Daily Mail linked her death to the others. Eskridge, an Alabama-based researcher, revealed in a rambling 2020 interview that she had plans to disclose information about UFOs and extraterrestrials, and was receiving threats as a result.

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The cases vary extensively in circumstance and span several years. JPL space researcher Frank Maiwald died in July 2024; his cause of death was not publicly disclosed. Anthony Chavez, a retired engineer who had worked at the Los Alamos National Laboratory in nuclear weapons research, disappeared from his New Mexico home in May 2025. An administrative assistant from the Los Alamos lab named Melissa Casillas went missing in June 2025; she was last seen walking along a highway a few miles from her home. Monica Jacinto Reza was employed as Director of Materials Processing at JPL when she vanished while hiking with a friend in the Angeles National Forest last June. Steven Garcia, a property custodian with high-level clearance at a national nuclear security administration facility in Albuquerque, disappeared last August. Pharmaceutical scientist Jason Thomas went missing last December; he was found dead on March 17, 2026.

What are the conspiracy theories?

The common thread between the 11 dead and missing seems to be that all of them had access to sensitive nuclear and aerospace research. The press release announcing the investigation by the House Oversight Committee says “these deaths and disappearances may represent a grave threat to U.S. national security and to U.S. personnel with access to scientific secrets.” Online sleuths say the cases are linked because they were working on projects tied to the development of clean energy, while Rep. Eric Burlison told Fox News, “This has all the hallmarks of a foreign operation.” 

Critics say it’s simply a conspiracy theory. Retired FBI agent Jennifer Coffindaffer told Newsweek that the claims “fall apart when examined under basic investigative principles.” Erin Ryan, co-host of the political commentary podcast Hysteria, called it a symptom of MAGA’s anti-science rhetoric: “I think that it’s a way for people on the far right to try to wash their hands of their culpability in creating an environment that’s actually dangerous to scientists.” The Atlantic‘s Daniel Engber wrote, “To call it a conspiracy theory would be far too kind, because no comprehensive theory has been floated to explain the pattern of events.” All in all, Engber said, the story is “unbelievably dumb.”

Why is there a federal probe?

The tale of the missing and dead scientists snowballed when GOP officials claimed it was serious news. On April 15, Fox News reporter Peter Doocy asked White House press secretary Karoline Leavitt about the scientists; two days later, Leavitt announced that the White House would launch an investigation. Congresswoman Anna Paulina Luna (R-Fl.) posted, “If you are feeling uneasy about the amount of scientists that have gone missing, died, and recent suicides ref those scientists and others you are correct in your intuition.” Rep. James Walkinshaw (D-Va), who serves on the Oversight Committee with Comer and Burlison, struck a measured tone about the investigation, telling CNN, “The United States has thousands of nuclear scientists and nuclear experts. It’s not the kind of nuclear program that potentially a foreign adversary could significantly impact by targeting 10 individuals.” 

President Trump said this week that the investigation has yet to turn up evidence of a connection in the deaths and disappearances. “Some of them that we looked at are very sad cases, in some cases, some were sick. Some left this earth self-inflicted. Some had other things,” Trump told reporters. “We’re going to be doing a full report. And it’s very serious.”

What do the families of the scientists say?

Family members of the dead and missing are frustrated by the swirl of conspiracy theories. Michael David Hicks’ daughter said that speculation about her father’s death has shaken her. “From what I know of my dad, there’s no train of logic to follow that would implicate him in this potential federal investigation,” Julia Hicks told CNN. “I don’t understand the connection between my dad’s death and the other missing scientists. I can’t help but laugh about it, but at the same time, it’s getting serious.” 

Amy Eskridge’s father, Richard Eskridge, a former NASA scientist, denied that his daughter’s suicide was suspicious, saying, “Scientists die also, just like other people.” William McCasland’s wife wrote on Facebook that, when McCasland was in the Air Force, he had access to “some highly classified programs and information,” but that he had been retired for more than a decade. “It seems quite unlikely that he was taken to extract very dated secrets from him.” 

Despite the federal investigation, Monica Jacinto Reza’s family says that no one from the White House or the FBI has contacted anyone in the family regarding her disappearance. They reject any suggestion that Reza was working on something that could have endangered her life. Speaking to LA Mag, one of Reza’s relatives said, “She was just a regular person who had a family.” 

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Whether or not they’re credible, the conspiracy theories keep coming. Mercury News reported that Rep. Burlison presented two more names that he says warrant scrutiny — Matthew James Sullivan, a former Air Force intelligence officer who died from a drug overdose in 2024, and Ning Li, an anti-gravity physicist who died in 2021 at the age of 79 after being struck by a car. There’s also the case of Joshua LeBlanc, a NASA nuclear scientist who died in a car crash in Alabama last year. 

On April 30, Burlison posted on X: “The count is up to 13. Thirteen American scientists tied to nuclear and space research, missing or dead. Every adversary on the planet celebrates each one we lose. We are weaker as a nation today because of these losses, and I’m working to get answers.”