FBI probes missing scientists mystery as nuclear lab worker found dead

The body of a missing nuclear researcher has been found nearly a year after she vanished, and after US officials launched a probe into a spate of scientists’ disappearances.

New Mexico State Police said they had identified the remains of Melissa Casias, 54, who was last seen alive on June 26, 2025.

Casias, who worked at the Los Alamos National Laboratory, a nuclear research facility in New Mexico, was reported missing after failing to show up for work. Her keys, phone, and purse were later found inside her home.

State police said in a statement over the weekend that her body was found in the McGaffey Ridge area of the Carson National Forest, alongside a handgun.

A hiker in the forest made the discovery, police added, and officials later confirmed that it belonged to Casias.

Her disappearance had been linked to a string of missing person cases involving US scientists, which have fuelled internet conspiracy theories.

At least 10 scientists connected to sensitive US nuclear and aerospace research are thought to have disappeared or died under mysterious circumstances in recent years, prompting the Federal Bureau of Investigation (FBI) to launch a probe in April.

Announcing the investigation, FBI Director Kash Patel said: “We’re going to look for connections … on 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.”

‘Pretty serious stuff’

Donald Trump also weighed into the mystery, with the US president saying in April that it was “pretty serious stuff” and that some of the people who had died or been reported missing were “very important people”.

The House Oversight Committee also sent letters to the US departments of energy and defence, as well as NASA and the FBI, in April as it sought information about “a possible sinister connection between a string of mysterious deaths and disappearances”.

Casias is thought to be the first missing scientist being investigated as part of the probe whose body has now been found.

She vanished after dropping her husband off for work at the Los Alamos National Laboratory, the same nuclear research facility where she worked. The scientist claimed she needed to return home after forgetting the ID badge she needed to access the laboratory.

Casias was last seen by a family acquaintance walking eastbound along a state highway near Talpa in New Mexico on June 26, 2025.

It is unclear if she owned the handgun found alongside her body, and police said they were making further enquiries.

Other cases being scrutinised include another former worker from the Los Alamos National Laboratory. Anthony Chavez, who had retired from his role as a foreman at the laboratory, was last seen leaving his home in New Mexico on May 4 last year.

The deaths of two NASA scientists and a researcher at the space agency are also being investigated, as well as a former senior air force engineer who had been involved in UFO research after his retirement.

The nature of the scientists’ work – which spans nuclear science, astrophysics, aeronautics and aliens – has fuelled speculation in recent weeks that they might all be connected.

It has also proved ripe for wild conspiracy theories, which have variously posited potential foreign interference and even extraterrestrial involvement behind the scientists’ cases.

In a statement reported by the New Mexico news outlet KRQE after the recovery of Casias’s remains, her family said: “There will be more information to come but what we can tell you now is she was located in an area previously searched.

“This is a lot to process, our hearts are heavy, and we fully intend to continue to pursue answers for justice.”

The Telegraph, London

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