Susan Wilkerson was gone for just more than one hour when her husband, retired Air Force Maj. Gen. William “Neil” McCasland — who once oversaw some of the military’s most advanced and highly classified research programs — reportedly vanished from their Albuquerque home.
McCasland, 68, left his phone behind, but his wallet and a .38-caliber revolver were missing, according to the Bernalillo County, New Mexico, Sheriff’s Office.
The general previously had said he was experiencing what he described as a “mental fog,” according to investigators, but authorities stressed there was no indication he was disoriented at the time of his disappearance.
“Arguably, he would still be the most intelligent person in the room,” Albuquerque police Lt. Kyle Wood said March 16.
McCasland’s disappearance is one of 10 recent cases involving scientists tied to U.S. military and government research that have drawn attention, including at the White House, where officials said they are looking into the matter after being asked about a potential pattern.
“I hope it’s random, but we’re going to know in the next week and a half,” Trump told reporters Thursday. “I just left a meeting on that subject.”
Here’s what we know about the scientists who have disappeared or died under a range of circumstances over the past three years.
McCasland disappeared Feb. 27 and police have found no trace of him since. His phone, prescription glasses and wearable devices were found at home, but his hiking boots, wallet and a .38‑caliber revolver were reported missing, according to the Bernalillo County, New Mexico, Sheriff’s Office.
McCasland held senior roles in space research and acquisition, including leadership positions at the Air Force Research Laboratory and the National Reconnaissance Office, according to the Air Force. He held senior roles at the Pentagon and commanded the Phillips Research Site of the Air Force Research Laboratory at Kirtland Air Force Base in New Mexico, and the Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio, according to the Air Force.
McCasland’s name also surfaced in an unexpected place years earlier — the 2016 WikiLeaks release of emails from Hillary Clinton campaign chairman John Podesta. In those messages, musician and UFO enthusiast Tom DeLonge described working with McCasland on discussions related to unidentified aerial phenomena, noting that the general had previously led the Air Force Research Laboratory at Wright-Patterson Air Force Base — a facility long tied in UFO lore to the alleged 1947 Roswell crash.
“Neil does not have any special knowledge about the ET bodies and debris from the Roswell crash stored at Wright-Patt,” his wife, Susan, wrote on Facebook shortly after his February disappearance.
The 1947 Roswell incident involved debris later identified by the U.S. government as part of a classified military balloon program, though it has long been the subject of UFO and extraterrestrial conspiracy theories.
Susan Wilkerson also noted that her husband retired in 2013.
“It seems quite unlikely that he was taken to extract very dated secrets from him,” she said on Facebook.
Reza, 60, was hiking with a friend in the Angeles National Forest near Los Angeles on a well-traveled trail around 9 a.m. on the morning of her disappearance, according to the Los Angeles County Sheriff’s Department.
The friend was about 30 feet ahead, and told police he turned around to check on her and she smiled and waved, indicating she was doing fine. The friend turned back to continue hiking, and when he looked back again moments later, she was gone, according to, according to case details released during the search.
He immediately alerted authorities who sent out a search party. Since then, there have been no sightings or any trace of Reza or her belongings.
Reza, an aerospace engineer, was the co-creator of Mondaloy, a nickel-based alloy capable of withstanding the extreme heat of rocket engines. At the time of her disappearance, she was the Director of Materials Processing at NASA’s Jet Propulsion Laboratory (JPL).
Reza’s work in advanced rocket materials was funded in part by the Air Force Research Laboratory — the same organization McCasland later led — placing the two in overlapping corners of the U.S. defense research ecosystem, though no direct relationship between them has been publicly confirmed.
Garcia, 48, was last seen leaving his home in Albuquerque around 9 a.m., captured on surveillance footage walking away on foot while carrying a handgun. He left behind his phone, wallet, keys and car, and has not been seen since, according to Albuquerque police.
Garcia was a government contractor tied to the Kansas City National Security Campus, a key facility responsible for producing the vast majority of non-nuclear components used in the U.S. nuclear weapons arsenal. His role reportedly gave him high-level security clearance and oversight of sensitive assets.
Authorities initially warned Garcia “may be a danger to himself,” raising concerns about his mental state. But an anonymous source familiar with the case pushed back on that assessment to the Daily Mail, describing him as “a very stable person” and disputing suggestions that he was suicidal or experiencing mental health issues.
Both Garcia and McCasland lived in the same region of New Mexico, a hub for U.S. nuclear and defense research, though authorities have not confirmed any connection between the cases.
Grillmair, 67, a California Institute of Technology astrophysicist known for his work on exoplanets and the discovery of water on distant worlds, was shot and killed outside his home in Llano, California, early in the morning. Deputies responding to a call found him on his front porch with a gunshot wound; he was pronounced dead at the scene.
Authorities later arrested a 29-year-old suspect in connection with the killing, charging him with murder as well as carjacking and burglary in separate incidents. Investigators said the suspect had previously been reported for trespassing on Grillmair’s property in the weeks leading up to the shooting.
Grillmair had spent decades working on major NASA-backed missions, including the Hubble and Spitzer space telescopes, contributing to research on galactic structure, dark matter and the search for habitable planets.
Loureiro, 47, a renowned MIT physicist and director of the university’s Plasma Science and Fusion Center, was shot at his home in Brookline, Massachusetts, and died from his injuries the following day.
His killing came within months of both the disappearance of McCasland and the fatal shooting of Grillmair, adding to growing attention around a series of cases involving scientists tied to defense and aerospace research.
Loureiro was a leading figure in fusion energy research, studying plasma physics and working on technologies aimed at harnessing near-limitless clean energy.
Authorities later linked his killing to a suspect connected to a separate mass shooting at Brown University days earlier. Investigators said the suspect, who had previously attended university with Loureiro in Portugal, died by suicide after the attacks, effectively closing the case.
Despite early speculation online, officials have not indicated Loureiro’s death was connected to his research or to any broader pattern.
Maiwald, 61, a longtime engineer at NASA’s Jet Propulsion Laboratory, died in Los Angeles on Independence Day.
The only widely available public record of Maiwald’s death is a brief online obituary. No cause of death has been publicly disclosed, and reporting indicates no autopsy was performed.
Maiwald spent decades at JPL developing advanced instruments used to study Earth and distant planetary environments, including tools capable of detecting chemical signatures such as water and organic molecules.
His work focused on building instruments capable of detecting chemical signatures including water, organic molecules and other indicators scientists use to assess whether environments beyond Earth could support life.
Casias, 53, was last seen on June 26, 2025, in Taos County, New Mexico, walking alone along State Road 518 near the community of Talpa.
Earlier that day, Casias, an administrative employee with security clearance at Los Alamos National Laboratory, had left work and spent time in Taos. At one point, her niece told local media, she picked up a Subway sandwich and dropped it off for her daughter, who was working at a coffee shop in the Taos Plaza area.
When family members returned home, they found her car, purse, keys and both her personal and work-issued phones inside. The phones had been factory reset, wiping recent data and communications.
Family members have strongly pushed back on the idea that she left voluntarily. “All of her friends keep telling us this is not like her… she wouldn’t leave her daughter,” her sister, Trudy Najera, said. The family added that Casias had been preparing to care for their mother during an upcoming surgery.
Despite multiple searches, no confirmed trace of Casias has been found since that afternoon.
Chavez, 78, a retired Los Alamos National Laboratory employee, is believed to have last been seen around May 4, 2025, at his home in Los Alamos, New Mexico. He was reported missing four days later, May 8.
When authorities and family members searched his home, they found his wallet, keys and other personal items left behind inside, while his car remained locked in the driveway. There were no signs of forced entry or a struggle, according to the Los Alamos Reporter.
Investigators reviewed hours of surveillance footage from nearby homes and businesses but have not publicly identified any confirmed footage showing Chavez after he left his residence.
Chavez had worked for decades at Los Alamos National Laboratory before retiring in 2017, placing him within the same northern New Mexico defense corridor as others who later vanished.
Thomas, 45, an associate director of chemical biology at pharmaceutical company Novartis, was reported missing in December 2025 after leaving his home in Wakefield, Massachusetts, late at night. Surveillance footage captured him walking near train tracks shortly after midnight, and he left behind his phone and wallet.
Thomas worked in chemical biology, a field at the intersection of chemistry and biology that uses small molecules to study and manipulate biological systems — work that plays a central role in modern drug discovery and the development of new treatments.
At Novartis, he focused on identifying and testing compounds that could target disease-related proteins, part of a broader effort to develop new medicines for complex conditions.
In the months after his disappearance, authorities conducted extensive searches but found no trace of him. On March 17, 2026, a body believed to be Thomas was recovered from Lake Quannapowitt after the ice thawed. Officials said no foul play was suspected, though the cause and manner of death have not been publicly disclosed.
The overlap in timing and profession has fueled questions about whether something more is at play. But investigators have not identified any evidence of a broader pattern, and the cases themselves, ranging from confirmed homicides to disappearances and natural deaths, point in different directions.
