The FBI is leading the effort to look for possible connections in the cases of ten missing or deceased scientists and staff who worked at sensitive nuclear or space technology laboratories, according to senior law enforcement officials. Meanwhile, conspiracy theories continue to abound online.
In a statement on April 21, the FBI said they are leading the investigation and working closely with the Department of Energy, the Department of Defense, and state and local enforcement agencies to figure out what happened and why, according to CBS News.
President Trump mentioned concerns about the situation. “I just left a meeting on that subject, so pretty serious stuff,” Trump said to reporters on April 23. “Hopefully coincidence, but some of them were very important people, and we are going to look at it.”
Separately, the Republican-led House Oversight Committee announced on April 20 that they will investigate reports of the deaths and disappearances of individuals who had access to sensitive scientific information, according to CNN News.
The cases vary widely in circumstances. In at least two instances, families have pointed to preexisting medical conditions or personal struggles as explanations, but authorities have not established any links between the cases.
The string of mysterious deaths and disappearances began in 2023 with the death of Michael David Hicks, a scientist who worked at NASA’s Jet Propulsion Laboratory (JPL) for nearly 25 years. Hicks died at 59 on July 30, 2023. During his career at JPL, he specialized in comets and asteroids, according to the American Astronomical Society. His cause of death was not disclosed.
In the years since, several others connected to JPL have also died or disappeared. Frank Maiwald, for example, was a specialist in space research and died in Los Angeles in 2024 at the age of 61. Another example is Monica Reza, a 60-year-old aerospace engineer who disappeared while hiking near Mount Waterman in the Angeles National Forest in June 2025. Yet another missing person is William Neil McCasland, a retired Air Force major general who went missing on Feb. 27 of this year. He left his home without his phone, wearable devices, and his prescription glasses. All he had with him were a pair of hiking boots, his wallet, and a 38-caliber revolver.
Scott Roecker, Vice President for Nuclear Materials Security at the Nuclear Threat Initiative, said the current war in Iran may factor into people’s thinking.
“If you were looking at a foreign adversary, Iran might come to mind because of the Iranian nuclear scientists who have been assassinated,” Roecker said. “But we are not like Iran. We have thousands of scientists and a robust infrastructure, so there would be nothing tragic Iran could achieve by taking out ten or twenty of our nuclear scientists, as tragic as the individual deaths may be.”
Online theorists also linked a case that appears to have already been solved: the killing of 47-year-old Nuno Lourerio, a physics professor at the Massachusetts Institute of Technology. Loureiro was gunned down in December by Claudio Manuel Neves Valente, who two days earlier had opened fire at Brown University. After the incident, Neves Valente died by suicide.
The Justice Department has not announced a motive for why Neves Valente could have targeted Brown. Both Loureiro and Neves Valente were from Portugal, according to NBC News.
While there have been no developments in the case in recent weeks, that has not stopped possible conspiracy theories from making their way around the internet. One of the more unique ones is from Mary Jane Gibson of Rolling Stone, who noted the following on May 4: “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?
