Canadian astrophysicist among dead and missing scientists at the centre of U.S. probe
A conspiracy theory suggesting a nefarious connection between the deaths, murders and disappearances of at least 10 individuals with ties to the U.S. scientific community has found its way to Washington and become the focus of a multi-agency investigation.
On Tuesday, in a statement to multiple media outlets, including CBS , the FBI announced that it was “spearheading the effort to look for connections into the missing and deceased scientists,” many of whom were reportedly involved in sensitive nuclear and aerospace research, including one murder victim who was an award-winning Canadian astrophysicist.
Meanwhile, state and local police across the country have found no evidence linking the cases, which date back to 2023, and family members have also dismissed any connection.
Here’s what to know as the story continues to develop.
Who is dead or murdered?
The most recent death tied to the conspiracy theory is that of Jason Thomas, a researcher for multinational pharmaceutical corporation Novartis, whose body was recovered from a Massachusetts lake this March.
His wife, who’d reported him missing in December, told NBC’s Dateline that the 45-year-old had been struggling with his parents’ recent sudden deaths at the time. His phone, wallet and Apple Watch were all left behind.
Authorities said foul play was not suspected.
A month prior, Calgary-born Carl Grillmair, an astrophysicist at the California Institute of Technology, was shot dead on the front porch of his remote Los Angeles County home. The 67-year-old’s research, according to the school , focused on dark matter, galactic structure, stellar populations and exoplanets. He collaborated with NASA often and was the recipient of the agency’s Exceptional Scientific Achievement Medal in 2011.
A 29-year-old man, whom Grillmair had called local police to have trespassed from his home about two months earlier, was later charged with his murder.
His death followed that of MIT professor Nuno Loureiro on Dec. 15, 2025, who was shot by Claudio Neves Valente, a former classmate from two decades prior in their native Portugal. Two days before killing Loureiro, an expert in fusion and plasma physics, authorities said Valente killed two people and wounded nine more in the mass shooting at Brown University . He was found with a self-inflicted gunshot wound on Dec. 18.
The July 2024 death of Frank Maiwald, a 61-year-old research scientist at NASA’s Jet Propulsion Laboratory (JPL) in California, has also been drawn into the investigation, according to CNN, as has his former coworker, physicist Michael David Hicks, 59, who died almost a year earlier.
The cause of death was never publicly disclosed in either case, but Hicks’ daughter has addressed the speculation.
“From what I know of my dad, there’s no train of logic to follow that would implicate him in this potential federal investigation. I don’t understand the connection between my dad’s death and the other missing scientists,” she told CNN.
“I can’t help but laugh about it, but at the same time, it’s getting serious.”
While not a scientist, per se, another person whose name has been bandied about is former U.S. Air Force intelligence officer Matthew James Sullivan, a 39-year-old who took his own life in 2024 before he could testify in a federal whistleblower case about UFOs.
“He was scheduled to come in for an interview. Within two weeks, he had suspiciously committed suicide,” Rep. Eric Burlison of Missouri told FOX .
Who is missing?
The highest-profile missing person, and the one whose disappearance catapulted the subject into the spotlight recently, is retired U.S. Air Force Major General William McCasland, who was last seen on a hiking trail near his home in Albuquerque, N.M., on the morning of Feb. 27.
The 68-year-old left home that day without his phone, prescription glasses, or any of the wearable devices the experienced hiker and avid outdoorsman would normally wear, CNN reported. Authorities have also not been able to find his wallet, his red backpack or his .38 revolver with a red leather holster.
The FBI was already looking into his disappearance, which had sparked online speculation about a conspiracy theory due to McCasland’s role as the commander of a research laboratory at Wright-Patterson Air Force Base. The Ohio facility is long-rumoured to be the U.S. government’s home for research into unidentified flying objects (UFOs) and wreckage from the alleged 1947 alien spacecraft crash in Roswell, N.M.
But McCasland’s wife, Susan McCasland Wilkerson , dismissed any notion that his disappearance was connected to his work because he retired almost 13 years ago and “had only very commonly held clearances since.”
“It seems quite unlikely that he was taken to extract very dated secrets from him,” she wrote on Facebook in March.
“Neil does not have any special knowledge about the ET bodies and debris from the Roswell crash stored at Wright-Patt. Though at this point with absolutely no sign of him, maybe the best hypothesis is that aliens beamed him up to the mothership. However, no sightings of a mothership hovering above the Sandia Mountains have been reported.”
Local police have said they don’t suspect foul play.
McCasland’s disappearance resulted in renewed scrutiny over the June 2025 disappearance of 60-year-old aerospace engineer Monica Reza, who served as the director of the NASA JPL materials processing group.
Reza was hiking with a companion in a forest outside Los Angeles when she suddenly disappeared. She is yet to be found, despite extensive searches of the area.
Officials in Albuquerque are also looking into the August 2025 disappearance of 48-year-old Steven Garcia, reportedly a property custodian with high-level clearance at the National Nuclear Security Administration’s Kansas City National Security Campus in the city, where non-nuclear components for nuclear weapons are manufactured, per News Nation Now .
Meanwhile, also missing are two individuals who worked at the Los Alamos National Laboratory, a leading nuclear research facility, in New Mexico.
Melissa Cassia , a 53-year-old married mother of one who worked as an administrative assistant at the lab, went missing under suspicious circumstances in June 2025, leaving behind all personal items. NBC reported that her phones had been factory reset.
“Melissa was an administrative assistant and did not have high-level clearance,” her niece, Jazmin McMillen, told CBS, noting she hasn’t seen any evidence linking it to other cases.
About a month earlier, 78-year-old Anthony Chavez , who retired from his position as a construction foreman at the site, was also reported missing. He was last seen leaving his home on foot.
On Facebook , his friend Carl Buckner noted that Chavez left behind his wallet, keys and personal items.
Officials told CNN foul play is not suspected in either case.
What has Donald Trump and his administration said?
The president was asked about the reports last week and said he hoped it was “random.”
“We’re gonna know in the next week and a half,” he told reporters outside before boarding a helicopter. “I just left a meeting on that subject, so… pretty serious stuff.”
REPORTER: Ten missing scientists with access to classified stuff, Nuclear material, Aerospace, they've all gone missing or turned up dead in the last couple months...what do you think is happening here?
— Donald J Trump Posts TruthSocial (@TruthTrumpPost) April 16, 2026
PRESIDENT TRUMP: Well, I hope it's random, but we're going to know in the… pic.twitter.com/pe1khdyhpR
On X , White House press secretary Karoline Leavitt said 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.”
“No stone will be unturned in this effort,” she wrote.
Speaking on FOX’s Sunday Morning Futures , FBI director Kash Patel said his office, in conjunction with the Department of Energy, the Department of Defence (War) and law enforcement agencies, will investigate “whether there are connections to classified access, access to classified information, and or foreign actors.”
“If there’s any connections that lead to nefarious conduct or conspiracy, this FBI will make the appropriate arrest,” he said.
Rep. Eric Burlison and Republican counterpart James Comer, representative for Kentucky, have been leading efforts to have the cases investigated for a potential connection. As members of the House Committee on Oversight and Government Reform, they sent letters to Patel, Secretary of Defence (War) Pete Hegseth, Energy Secretary Chris Wright and NASA boss Jared Isaacman on Monday, requesting a “staff-level briefing on this topic” no later than this coming Monday, April 27.
“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,” they wrote.
Sunday on FOX , Comer said, “It’s very unlikely that this is a coincidence.”
FBI INVESTIGATES STRING OF DEAD SCIENTISTS
— The Evening Edit (@EveningEdit) April 22, 2026
GOP Rep Eric Burlison demands answers surrounding the 11 scientists that have died or gone missing since 2022@RepEricBurlison @FoxBusiness pic.twitter.com/4OBh3DCfQ1
Only Hicks, Reza, and McCasland were mentioned by name in the letter.
Meanwhile, spokesperson Bethany Stevens said on X that “nothing related to NASA indicates a national security threat” but that it was working with other agencies “in relation to the missing scientists.”
“The agency is committed to transparency and will provide more information as able,” she wrote.
CNN reported that the Defence Department would only respond to the committee directly, and the Department of Energy referred questions to the White House.
A National Nuclear Security Administration (NNSA) official told CBS it is “looking into the matter.”
Who believes it’s a coincidence?
There are plenty of people already throwing water on the idea that the cases are connected in some shady way.
Democratic Virginia Representative James Walkinshaw, who sits on the oversight committee with Comer and Burlison, said an investigation is warranted, but doubts the handful of cases are connected.
“The United States has thousands of nuclear scientists and nuclear experts,” he told CNN’s Erin Burnett this week. “It’s not the kind of nuclear program that potentially a foreign adversary could significantly impact by targeting 10 individuals.”
The deputy director of the Project on Nuclear Issues at the Center for Strategic and International Studies noted that the cases are spread over several years and involve people at “different and loosely affiliated organizations.”
“ If all of the scientists were working on one project or weapons system, then I’d be more suspicious,” Joseph Rodgers told CBS.
The outlet also spoke with Scott Roecker, vice president for nuclear materials security at the Nuclear Threat Initiative, who suggested the recent war in Iran may be affecting people’s judgment because some of that country’s nuclear scientists have been assassinated.
“But we’re not like Iran. We have thousands of scientists. We have a robust infrastructure. So there would be nothing strategic Iran could achieve by taking out 10 or 20 of our nuclear scientists, as tragic as the individual deaths might be,” Roecker said.
Paranormal investigator Benjamin Radford told Vanity Fair that, like most conspiracy theories, “once you start looking into the details, the mystery sort of vanishes.”
He went on to add that some people pushing the connection theory “a re working backward.”
“They’re finding people who are already dead or missing and then trying to find some connection, however tenuous, to the defence industry, the Pentagon, UFOs, UAP, NASA.”
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