A sweeping federal investigation has been launched into a chilling string of deaths and disappearances involving scientists linked to highly sensitive U.S. research, raising urgent national security questions as authorities search for answers across multiple agencies and states.

At least 10 scientists and staff connected to classified or sensitive scientific work are now part of an FBI-led probe, including four individuals from the Los Angeles area, according to federal officials.

Investigation Expands as National Agencies Mobilize

“The FBI is spearheading the effort to look for connections into the missing and deceased scientists. We are working with the Department of Energy, Department of War, and with our state and state and local law enforcement partners to find answers,” the agency said in a statement.

The announcement signals a rapidly expanding inquiry involving federal and local partners as investigators attempt to determine whether the cases are linked or purely coincidental.

The House Oversight Committee has also launched its own investigation, sending formal letters to multiple federal agencies, including NASA, which oversees the Jet Propulsion Laboratory in La Cañada Flintridge. Three of the scientists at the center of the FBI review were affiliated with the facility.

“If the reports are accurate, these deaths and disappearances may represent a grave threat to U.S. national security and to U.S. personnel with access to scientific secrets,” Reps. James Comer (R-Ky.), chairman of the committee, and Eric Burlison (R-Mo.) wrote in the letters.

President Trump said last week he had been briefed on the situation and described it as highly concerning.

“pretty serious stuff.”

He also indicated he expected more clarity soon.

“in the next week and a half.”

A Series of Disturbing Cases Across Four Years

The timeline under investigation stretches over several years and includes both unexplained deaths and missing person cases.

Michael David Hicks, a comet and asteroid researcher at JPL, was the first known case. He died on July 30, 2023, at age 59. No cause of death was released.

About a year later, JPL physicist Frank Maiwald died at 61. Officials also did not disclose a cause of death.

Two additional Los Angeles area scientists are part of the broader inquiry.

On June 22, 2025, Monica Jacinto Reza, a materials scientist at JPL, vanished while hiking near Mt. Waterman in the San Gabriel Mountains.

On Feb. 16, Caltech astrophysicist Carl Grillmair was shot and killed on the porch of his Llano home. Authorities later arrested 29 year old Freddy Snyder in connection with the killing. Snyder had previously been arrested in December on suspicion of trespassing on Grillmair’s property and has since been charged with murder.

Despite the alarming pattern, investigators stress there is no confirmed connection between the cases.

Authorities Urge Caution as No Link Has Been Found

Law enforcement officials and scientists involved in the review have emphasized that, at this stage, no evidence shows the cases are connected, despite public concern and growing scrutiny.

NASA, which owns and oversees JPL, said it is cooperating fully with investigators.

“At this time, nothing related to NASA indicates a national security threat,” agency spokesperson Bethany Stevens wrote. “The agency is committed to transparency and will provide more information as able.”

Caltech, which manages JPL, said it is aware of the federal inquiry but has not been directly contacted regarding it.

Emily Velasco, a Caltech spokesperson, said the institution is still coping with the loss of Grillmair.

“He was a beloved colleague, and his loss has deeply affected many people here,” she said.

Meanwhile, the Los Angeles County Sheriff’s Department confirmed that the disappearance of Monica Jacinto Reza remains an open investigation.

“At this time, there are no clear indications of foul play; however, investigators are continuing to evaluate all possibilities and are not ruling anything out,” the statement said.

Officials added that they have consulted with other law enforcement agencies across state lines but have found no evidence linking Reza’s disappearance to similar cases elsewhere.

As federal investigators widen their reach, the central question remains unanswered: whether these separate tragedies are isolated incidents or part of something far more serious.