A fusion professor’s killing and two unresolved disappearances have drawn national attention because of the victims’ work in advanced science and defense research.
WASHINGTON, DC — The killing of an MIT fusion leader and the unresolved disappearances of a retired Air Force major general and a California aerospace engineer have fueled fresh national security concerns, even as authorities in three investigations have not publicly tied the cases together.
What is known is serious enough on its own. Nuno F.G. Loureiro, 47, director of MIT’s Plasma Science and Fusion Center, died in December after he was shot at his home in Brookline, Massachusetts. Monica Reza, 60, vanished during a June 2025 hike in the Angeles National Forest. William Neil McCasland, 68, a retired Air Force major general who once led major research commands, disappeared from his Albuquerque-area home on Feb. 27. The cases matter now because each remains part of a broader public debate over the safety of people working around sensitive research, even though investigators have released no public proof of a coordinated plot.
Loureiro’s case is the most developed. Police and prosecutors said he was shot on the night of Dec. 15, 2025, at his Brookline home and died early the next day. MIT President Sally Kornbluth called it “tragic news” in a message to the campus, and the loss shook a research community that had looked to Loureiro as one of the country’s prominent voices in plasma physics and fusion science. Two days later, on Dec. 18, federal and local authorities said the same suspect was believed responsible for both Loureiro’s killing and the earlier Dec. 13 mass shooting at Brown University in Providence, Rhode Island. The suspect, Claudio Manuel Neves Valente, was found dead of a self-inflicted gunshot wound in a storage facility in Salem, New Hampshire, ending a multistate manhunt just before Christmas. Prosecutors later released transcripts from videos attributed to the suspect, saying they still had not established a clear motive for targeting Loureiro.
The two disappearance cases are far less settled. Reza was last seen at about 9:10 a.m. on June 22, 2025, near the Mount Waterman area off Angeles Crest Highway in Los Angeles County. Authorities described her as an experienced hiker and said search teams moved quickly into the rugged forest terrain after she failed to return. Public notices described her as 4 feet, 11 inches tall and about 101 pounds, wearing a red long-sleeve shirt, green hiking pants and hiking shoes. Search-and-rescue crews, sheriff’s deputies and air units canvassed the area in the first days after she vanished, but no public announcement has said she was found. McCasland disappeared months later, on Feb. 27, from the Sandia Heights area near Albuquerque. A timeline released by the Bernalillo County Sheriff’s Office said he spoke with a repairman at about 10 a.m.; his wife returned home at 12:04 p.m. and found him gone. He was reported missing at 3:07 p.m. Authorities later said his phone and glasses were left behind.
The backgrounds of the missing pair have added to the attention. Reza has been described in news accounts as an aerospace engineer and materials scientist with work connected to rocket and defense research. McCasland held senior Air Force positions tied to research and development, including leadership roles at Kirtland Air Force Base and the Air Force Research Laboratory. Those résumés have pushed the cases out of the usual local-crime lane and into a national conversation shaped by secrecy, defense contracting and public mistrust. But the public record remains narrower than the speculation. In Reza’s case, law enforcement notices have centered on a missing-hiker investigation in steep terrain, not sabotage. In McCasland’s case, the sheriff’s office has said only that investigators have not ruled out whether he is alive, deceased, or whether foul play may be involved. That is a broad statement, not proof of a national security breach. So far, no agency has publicly said the three cases share suspects, methods or evidence.
Even so, each case sits in a setting that gives it extra weight. Loureiro led a major center studying plasma behavior and fusion, an area watched closely by universities, private industry and governments seeking future energy breakthroughs. Reza vanished in a vast national forest outside Los Angeles where rescue operations can be slowed by elevation, weather and heavy tree cover. McCasland’s disappearance came from a neighborhood close to one of the country’s best-known military research hubs. In New Mexico, the sheriff’s office issued a Silver Alert because of concerns about his welfare and has continued public briefings as the search stretched into March. The FBI joined that effort, another step that intensified attention. Yet investigators have been careful not to validate sweeping theories that spread online. McCasland’s family has also pushed back on claims that his disappearance proves hidden knowledge or a targeted campaign, saying public rumor has outrun confirmed fact.
The next steps are mostly procedural, and they differ by case. In Massachusetts and Rhode Island, Loureiro’s killing now sits within the documented trail of evidence gathered after the Brown shooting and the suspect’s death, with prosecutors still filling in motive and timeline details. In California, Reza remains listed as a missing person, and the unanswered question is basic but crucial: whether new evidence can show where she went after she was last seen on the trail. In New Mexico, authorities have continued to ask for surveillance footage, public tips and any sign of McCasland’s movements during the narrow window when he vanished. The Bernalillo County Sheriff’s Office said in a March update that all possibilities remain under review. That means the most important milestones may not be arrests or hearings, but search findings, forensic results and any verified sighting or recovered evidence that can move one of the cases from mystery to explanation.
For the people closest to the cases, the story is less about espionage than absence. Colleagues at MIT remembered Loureiro as a scientist, mentor and friend whose death stunned students and researchers days before the winter holidays. In Los Angeles County, the early search for Reza carried the familiar urgency of a missing-hiker case, with teams combing brush and trail corridors where a small delay can sharply lower the odds of a safe recovery. In Albuquerque, neighbors and deputies have spent weeks looking for a man known in military circles for technical leadership but known at home simply as a husband and community member who went missing in a matter of minutes. The public fascination has grown because all three names touch institutions associated with high-level science or defense work. The investigations, however, still point to a more cautious conclusion: three grave cases, two of them unsolved, and no public evidence yet that they are part of a single operation.
As of March 24, Loureiro’s killing appears tied to an identified suspect who is dead, while Reza and McCasland remain missing. The next milestone is likely to come from law enforcement updates in California or New Mexico, where both searches remain open.
Author note: Last updated March 24, 2026.