Nuno Loureiro
Republicans speak of a “possible sinister connection” that could pose a “serious threat” to the national security of the United States. Portuguese physicist was killed on his doorstep in December.
The FBI is investigating a possible link between the death or disappearance of 10 scientists and experts linked to sensitive areas in the United States, including the nuclear and aerospace sectors.
Among the cases under scrutiny by the agency is that of the Portuguese physicist Nuno Loureirodirector of the Plasma and Fusion Science Center at the Massachusetts Institute of Technology (MIT), in December 2025.
The House of Representatives Supervisory Committee also opened a parallel investigation. According to , federal authorities admit that, so far, no formal link has been established between the victims or between the circumstances of each case. Still, the FBI confirmed that it is leading efforts to look for patterns or commonalities, in coordination with the Department of Energy, the Department of Defense and several state and local law enforcement agencies.
Fears center on the fact that several of those targeted are linked to sensitive scientific researchwith access to strategic information related to space technology, defense or projects with implications for North American national security.
It was this coincidence that helped fuel several conspiracy theories recently, and public suspicions of an eventual targeted elimination campaign.
Supposedly, Nuno Loureiro would be on the verge of a “revolutionary” discoverydescribed himself in the year before his death, to Domingo do magazine: obtaining an energy source from nuclear fusion that would be competitive compared to oil.
The case of Nuno Loureiro, murdered on his doorstep four months ago in Boston, became one of the best known on this FBI list.
The author of the murder has not yet been fully clarified. North American authorities suspected the Portuguese man, a former colleague of Loureiro at Instituto Superior Técnico, who was also accused of a shooting at Brown University that caused two deaths. Valente was found dead two days later, in a New Hampshire warehouse, in a case treated as an apparent suicide.
In addition to Loureiro, the list highlights the disappearances of , a retired US Air Force major general, and Monica Jacintoaerospace engineer. Both had ties to the Air Force Research Laboratory. Jacinto disappeared in July 2025, and McCasland in February 2026, under similar circumstances: both will have disappeared during walkswithout leaving a trace.
The list also includes other episodes recorded since July 2023. One of the examples cited is that of Michael David Hicksa scientist who worked for almost 25 years at NASA’s Jet Propulsion Laboratory. Although the cause of death was classified as natural, due to arteriosclerotic cardiovascular disease, the case remains open in the records of the Los Angeles County coroner.
Two Republican congressmen, Eric Burlison and Tim Burchett, have publicly insisted on the need to see if there is a link between these episodes. Burlison then joined James Comer, chairman of the House Oversight Committee, in asking for formal information from the Department of Energy, the Department of Defense, the FBI and NASA.
In a letter sent by both, the congressmen argue that these deaths and disappearances could represent a “serious threat” to the national security of the United States, especially because they involve professionals with access to scientific and technological secrets. The formulation used in the document speaks of a possible “sinister connection” enter disappearances or deaths.
US President Donald Trump himself commented on the matter: he said it was “quite serious” and promised clarifications soon. The following day, the White House reinforced this position: spokeswoman Karoline Levitt assured that the administration would work with all relevant agencies to analyze the cases together and identify possible common elements: “no effort will be spared”.
