Missing Scientists Mystery Goes Global: 20 Researchers Dead or Missing in US and China as FBI Probes Suspicious Deaths

A string of unexplained deaths and disappearances among elite American scientists has prompted a Federal Bureau of Investigation (FBI) probe, and Newsweek reporting now shows China faces its own cluster of at least nine mysterious fatalities in military artificial intelligence (AI), hypersonic weapons, and space defence.

The combined tally of roughly 20 researchers, 11 in the United States and nine in China, raises questions about whether their work is the common thread.

FBI Steps in as US Death Toll Hits 11

FBI Director Kash Patel confirmed this week that the bureau is leading a review of at least 10 cases linked to sensitive nuclear, space, and defence research, working with the Department of Energy and Department of War. The cases span Massachusetts Institute of Technology labs, NASA's Jet Propulsion Laboratory (JPL), Los Alamos National Laboratory, Caltech, and the Kansas City National Security Campus, dating to 2022.

Monica Reza, a 60-year-old JPL engineer who patented a nickel super-alloy for reusable rockets, vanished while hiking in June 2025. Retired Air Force Major General William Neil McCasland, 68, walked out of his Albuquerque home on 27 February 2026 and has not been seen since. President Donald Trump has called the sequence 'pretty serious stuff' while hoping it was coincidence.

The House Oversight Committee sent letters on 20 April 2026 demanding briefings from the FBI, NASA, the Department of War, and the Department of Energy by 27 April.

Nine Chinese Cases in the Same Fields

Newsweek has separately documented at least nine Chinese scientists who have died in unexplained circumstances over the past three years, with ages from 26 to 68. Obituaries and media reports have attributed the deaths to traffic accidents, unspecified 'accidents', or no cause at all.

Among them is Zhang Xiaoxin, 62, a space expert at China's National Satellite Meteorological Centre specialising in early warning systems. He died in a traffic accident in December 2024 after winning a top Chinese military science award.

The Chinese embassy in Washington told Newsweek it was 'not aware of the relevant situation' when asked about the pattern.

The 'Sacrificed' Military AI Pioneer

The most striking case is Feng Yanghe, a 38-year-old associate professor at China's National University of Defense Technology. State-run China Daily reported Feng died in a Beijing traffic accident at 2:35 a.m. on 1 July 2023 after leaving a work meeting. Officials said he had been working on a 'major task'.

An obituary on Sciencenet.cn, a state-run science news site, said Feng was 'sacrificed while performing official duties,' language typically reserved for soldiers killed in action. He was buried at Babaoshan, the Beijing cemetery reserved for Communist Party elites, state heroes, and revolutionary martyrs.

Feng designed 'War Skull', China's first AI system for military command and control, used by 10 People's Liberation Army (PLA) and defence industry departments by 2021.

Why the Pattern Is Raising Alarm

An anonymous researcher at a Western think tank told Newsweek the fields suffering losses are the same on both sides. 'The areas are in hypersonics, in military AI, including swarming technology simulations, stuff that could really make a difference. These types of tech seem to be overrepresented in the clusters,' the researcher said.

The same source said the aim might not be to wipe out a team but to slow rival programmes by removing 'some of the brightest minds doing path-breaking work.' Former FBI official Chris Swecker said the pattern fits how several foreign powers have operated.

Other experts urge caution. Joseph Rodgers of the Center for Strategic and International Studies noted the cases are 'scattered across several years at different and only loosely affiliated organisations.' Still, the international reach of this pattern has given the FBI probe fresh urgency.