President Trump said officials are looking into 10 cases of U.S. scientists who have either died or gone missing in recent years.
"I hope it's random, but we're going to know in the next week and a half," Trump told Fox News. "I just left a meeting on that subject."
All of the scientists were involved in military and government research. Although media reports have attempted to connect the various cases, each has very different circumstances.
Neil McCasland, a retired major general, disappeared from his home on February 27. Fox News reported that his glasses, phone and wearable devices were found at his home. Missing from the home were McCasland's hiking boots, his wallet, and a .38-caliber revolver.
Although McCasland once held senior roles in space research and acquisition at the Air Force Research Laboratory and the National Reconnaissance Office, he had been retired since 2013.
"It is true that when Neil was in the Air Force, he had access to some highly classified programs and information. He retired from the AF almost 13 years ago and has had only very commonly held clearances since. It seems quite unlikely that he was taken to extract very dated secrets from him," his wife, Susan McCasland Wilkerson wrote on Facebook to address speculation on the matter.
Another case is the death of 47-year-old Nuno Loureiro. Loureiro was a Massachusetts Institute of Technology physicist and director of the university's Plasma Science and Fusion Center. He was shot and mortally wounded at his home in Brookline, Massachusetts in December 2025.
However, federal authorities already believe they have solved Loureiro's murder. The Justice Department tied Loureiro's death to Brown University mass shooter Claudio Manuel Neves Valente, who later committed suicide. Valente's body was found in a storage unit.
Valente had previously attended Brown as a graduate student. His connection to Loureiro was through the University of Lisbon engineering and technology school. Both graduated from there in 2000.
Another murder that authorities believe they have already solved is that of Carl Grillmair, 67, a California Institute of Technology astrophysicist. Police in California have charged 29-year-old Freddy Snyder in Grillmair's death, Pasadena Now reported.
"While investigating the shooting call, Palmdale Sheriff's Station deputies also responded to a carjacking call in the same area," according to a statement released by the Los Angeles County Sheriff's Department. That subsequent call in the same area led to Snyder's arrest.
According to Pasadena now, Snyder had previously been charged with residential burglary last December 28, and was arrested in Palmdale last December 20 on suspicion of carrying a loaded firearm in a personal vehicle.
However, other cases being examined remain open and unsolved.
- In June 2025, 60-year-old Monica Jacinto Reza disappeared while hiking with a friend in California. According to Fox News, the friend had said Reza was about 30 feet away and the friend had just moments earlier turned around to check on and wave at her. The next time the friend turned around, Reza was gone. Despite a massive search effort, Reza was never found. Reza, was an aerospace engineer, who had helped create Mondaloy, a nickel-based alloy capable of withstanding the extreme heat of rocket engines. When she disappeared, she was the Director of Materials Processing at NASA's Jet Propulsion Laboratory (JPL), Fox News reported.
- In June 2025, Melissa Casias, 53, was reported missing. Fox News reported that she was last seen walking alone along State Road 518 near the community of Talpa in New Mexico. She was described by Fox as an administrative employee with security clearance at Los Alamos National Laboratory,
- In August 2025, Steven Garcia 48, disappeared from his home in Albuquerque around 9 a.m., Fox News noted. The network described Garcia as a government contractor who had ties to the Kansas City National Security Campus. Fox News reported that he was seen on surveillance footage leaving his home while carrying a handgun.
- Anthony Chavez, 78, had retired from Los Alamos National Laboratory in 2017. Fox News reported that authorities have not found any footage of him leaving his home or traveling. Chavez left his wallet, car keys and personal items in his home, according to the Los Alamos Reporter. He has not been seen since May last year.
- Jason Thomas, 45, an associate director of chemical biology at pharmaceutical company Novartis, was reported missing in December 2025 after leaving his home, Fox News reported. Thomas was seen walking near train tracks on surveillance video late at night. His body was later found in Lake Quannapowitt, Massachusetts, on March 17. Officials said no foul play was suspected. PEOPLE reported that before his death, Thomas had been struggling with the deaths of his parents.
- Frank Maiwald, 61, died in July 2024. Fox News reported that he was a longtime engineer at NASA's Jet Propulsion Laboratory. Maiwald's cause of death has not been released. An obituary page has 45 entries of people sharing their memories of him. "Frank's life was a testament to the power of dedication, love, and kindness. His legacy will continue to inspire those who knew him and benefited from his work and warmth," his obituary states.
