Federal investigations continued Wednesday into several recent disappearances or deaths of U.S. scientists — including at least four in the Pasadena area — to determine if the cases are connected with national security threats.
Indications of federal inquiries surfaced last week when President Donald Trump said he had received a briefing on the deaths and disappearances and that he would order an investigation. The next day, White House Press Secretary Karoline Leavitt confirmed plans for the probe.
“In light of the recent and legitimate questions about these troubling cases, and President Trump’s commitment to the truth, the White House is actively working with all relevant agencies and the FBI to holistically review all of the cases together and identify any potential commonalities that may exist,” Leavitt posted on social media. “No stone will be unturned in this effort, and the White House will provide updates when we have them.”
On Monday, the House Oversight Committee requested information from the FBI and other federal agencies about the mysteriously dead or missing scientists and other personnel connected to U.S. nuclear secrets or rocket technology.
A joint statement by Repuplican Reps. James Comer, R-Kentucky, chairman of the House Oversight Committee, and Eric Burlison, R-Missouri, chairman of the Subcommittee on Economic Growth, Energy Policy, and Regulatory Affairs, announced an investigation into unconfirmed reports on the disappearances and deaths of people with access to sensitive scientific information.
“These reports allege that at least 10 individuals who ‘had a connection to U.S. nuclear secrets or rocket technology,’ have ‘died or mysteriously vanished in recent years,'” according to Comer and Burlison. “If the reports are accurate, these deaths and disappearances may represent a grave threat to U.S. national security and to U.S. personnel with access to scientific secrets. We request a briefing on any information regarding these deaths and disappearances, as well as the processes and procedures in place to protect American scientific secrets and ensure personnel safety.”
The lawmakers said the string of questionable cases started with the 2023 death of Michael David Hicks, a former scientist at NASA’s Jet Propulsion Laboratory in Pasadena. No cause of death for the 59-year-old Hicks, who worked at JPL from 1998-22, was ever released.
In 2024, space scientist and JPL researcher Frank Maiwald died in Los Angeles at age 61. No cause of death was released.
JPL employee Monica Reza, who served as the director of the NASA facility’s Materials Processing Group, disappeared in June 2025 while hiking in the Angeles National Forest. The Los Angeles County Sheriff’s Department reported Reza was last seen hiking on Angeles Crest Highway. She has never been found.
In February of this year, renowned Caltech astrophysicist Carl Johann Grillmair, 67, was fatally shot on the front porch of his home in a remote part of the unincorporated community of Llano in the Antelope Valley near the border with San Bernardino County. A 29-year-old suspect was arrested and charged with murder in that case, although a possible motive for the crime has not been released. Deputies had arrested Llano resident Freddy Snyder for unrelated crimes and soon linked him to Grillmair’s shooting.
Grillmair, originally from Canada, was a noted astronomer hailed for discovering water on a distant planet. His work included research using NASA’s Spitzer Space Telescope.
According to published reports, a spokeswoman for NASA said Monday the agency “is coordinating and cooperating with the relevant agencies in relation to the missing scientists. At this time, nothing related to NASA indicates a national security threat. The agency is committed to transparency and will provide more information as able.”
At least six other scientists have disappeared or died in recent years, including a two employees at Los Alamos National Laboratory, a nuclear research facility in New Mexico.
The cases have fueled conspiracy theories questioning if the disappearances and deaths were connected and part of a broader threat to national security.
That speculation intensified in February when U.S. Air Force Maj. Gen. Neil McCasland went missing in New Mexico. McCasland had led research projects at Wright-Patterson Air Force Base, a focal point of UFO conspiracy theories alleging a government cover-up.
McCasland disappeared from his Albuquerque home with a .38 caliber revolver and remains missing, the congressmen reported. The other missing or deceased individuals are two affiliated with Los Alamos National Laboratory, an MIT scientist working on nuclear fusion, a pharmaceutical researcher and a government contractor working at a nuclear weapons component production facility.
