As reports of approximately a dozen cases involving missing or deceased American nuclear scientists emerge, a retired senior FBI official has noted a potentially troubling pattern.

“The nature of these disappearances is inherently suspicious,” commented Chris Swecker, a former assistant director of the FBI. “Given the sensitive nature of their work, it’s highly probable that hostile foreign intelligence services, such as those from Russia, China, Iran, or Pakistan, would take an interest.”

Swecker, however, points out that the six widely reported deaths appear to lack commonality, and he does not see evidence suggesting a direct connection among these cases.

Chris Swecker testified before a House Armed Services Subcommittee on Capitol Hill in Washington, D.C., on December 9, 2020. (Samuel Corum/Getty Images)

While Swecker remains skeptical about a broader conspiracy, particularly among the missing scientists, he concurs that investigators must explore potential links in these disappearances, considering the critical and sensitive nature of the technology involved in their work.

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.“

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.”

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.”

“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.