FBI probes mysterious disappearances, deaths of US scientists
House Oversight Committee demands answers as the FBI spearheads an investigation into the mysterious deaths and disappearances of US scientists involved in sensitive nuclear and space research. Former FBI Director Chris Swecker warns of potential espionage. Separately, an Iranian national was arrested at LAX for arms trafficking, alongside coverage of a Shreveport gunman killing 8 children and a fiery NYC street takeover.
NEWYou can now listen to Fox News articles!
As about a dozen cases involving missing or deceased American nuclear scientists have come to light, a retired high-level FBI official says some of them fit a pattern that he considers suspicious.
“The missing [and] disappearance thing is suspicious inherently,” said Chris Swecker, who served as assistant director of the FBI. “What they were working on would certainly, without a doubt, be a target of a hostile foreign intelligence service like Russia or China. It could be Iran, could be Pakistan.”
Swecker believes the six deaths that have been widely reported don’t have much in common, and he doesn’t believe they’re connected.
Chris Swecker testifies before a House Armed Services Subcommittee on Capitol Hill in Washington, D.C., on Dec. 9, 2020. (Samuel Corum/Getty Images)
While Swecker isn’t convinced that there’s a conspiracy afoot even among the missing scientists, he agrees that authorities should be looking for links in the disappearances, given the high-value, sensitive technology that they all worked with or near.
The disappearance of retired Air Force Maj. Gen. William Neil McCasland earlier this year set off the cascade of theories about the missing and dead scientists. He was the former commander of the Air Force Research Laboratory, and had connections to the Los Alamos National Laboratory, where top-secret nuclear research is conducted.

A split image shows retired Air Force Maj. Gen. Neil McCasland in the green shirt he was last seen wearing and in his military uniform. (Bernalillo County Sheriff’s Office, Neil McCasland/Facebook, Kirtland Air Force Base)
He vanished in New Mexico after leaving his home with only a pair of boots and a handgun. He left his phone, keys and glasses behind.
“I’m just saying that … the FBI would have interest in anything that happened to them because of what they were working on,” he said. “And, in fact, [with] McCasland, the FBI showed up uninvited that very afternoon.“
STATE DEPARTMENT EMPLOYEE ALLEGEDLY REMOVED CLASSIFIED DOCS, MET WITH CHINESE OFFICIALS
Anthony Chavez, 79, worked at Los Alamos National Laboratory until he retired in 2017. He reportedly disappeared on May 8, 2025. He was last seen leaving his house in Los Alamos on foot, with his car locked in his driveway. He did not bring his phone, wallet or keys on his walk.
Melissa Casias, 53, also worked at the Los Alamos National Laboratory. She went missing on June 26, 2025.
Steven Garcia, 48, went missing from Albuquerque on Aug. 28, 2025. He worked at the Kansas City National Security Campus, located in Albuquerque, which develops most of the nonnuclear components that go into building nuclear weapons. He reportedly left on foot carrying only a handgun.

Steven Garcia, 48, who worked at the Kansas City National Security Campus, was reported missing after leaving his Albuquerque home on foot carrying only a handgun on Aug. 28, 2025. (New Mexico Department of Public Safety)
He reportedly had a top secret security clearance.
“So Garcia, Chavez and Casias, in my opinion, ought to be lumped in and that should be the focus, and any others that went missing, because that would fit more of a pattern than just killing somebody because of what they know,” said Swcker.
“Exact same pattern,” he continued. “They disappeared with all their personal belongings [left] behind. Some of them took their handguns with them, which means they’re either in fear or they’re going to go use it on themselves.”
IS THERE A NEW ENGLAND SERIAL KILLER? FORMER FBI AGENT WITH REGIONAL TIES REVEALS HIS THEORY
Swecker also had a warning for scientists working in top-secret fields.

Anthony Chavez, 79, was reported missing after he was last seen leaving his home on foot in Los Alamos, N.M., on May 8, 2025. Chavez, a retired Los Alamos National Laboratory employee, left behind his car, phone, wallet and keys. His whereabouts remain unknown. (New Mexico Department of Public Safety)
“What people really need to be aware of — anybody involved in technology and anything that China or Russia or our competitors want to get their hands — ought to understand that there is a daily collection effort by China, Russia, Iran, to some extent, North Korea, but mainly China and Russia to steal technology because they’re not good at [research and development],” he said. “And their whole programs depend on stealing the technology and reverse engineering it.”
CLICK HERE TO DOWNLOAD THE FOX NEWS APP
“So, scientists, people involved in the defense contracting companies, research and development at universities, you know, all types of technologies in the U.S., even if it’s not military use, ought to be aware that this type of stuff goes on day in and day out.”
Last week, the White House directed the FBI to coordinate an investigation into the cases. The investigation is ongoing.

