WASHINGTON — Amid growing national security concerns, the FBI said Tuesday that it has launched a broad investigation in the deaths or disappearances of at least 10 scientists and staff connected to highly sensitive research, including four from the Los Angeles area.

“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 FBI’s announcement comes after the House Oversight Committee announced that it would investigate reports of the disappearance and deaths of the scientists, sending letters seeking information from the agencies involved in the federal inquiry as well as NASA, which owns the Jet Propulsion Laboratory in La Cañada Flintridge, where three of the missing or dead scientists worked.

“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 told reporters last week that he had been briefed on the missing and dead scientists, which he described as “pretty serious stuff.” He said at the time that he expected answers on whether the deaths were connected “in the next week and a half.”

Michael David Hicks, who studied comets and asteroids at JPL, was the first of the scientists who disappeared or died. He died on July 30, 2023, at the age of 59. No cause of death was disclosed.

A year later, JPL physicist Frank Maiwald died at 61, with no cause of death disclosed.

Two other Los Angeles scientists are part of the string of deaths and disappearances.

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

On Feb. 16, Caltech astrophysicist Carl Grillmair was fatally shot on the porch of his Llano home. The Los Angeles County Sheriff’s department arrested Freddy Snyder, 29, in connection with the shooting. Snyder had been arrested in December on suspicion of trespassing on Grillmair’s property.

Snyder has been charged with murder.

There is no evidence at this point that the deaths and disappearances, which occurred over a span of four years, are connected.

A spokesperson for NASA, which owns JPL, said in a statement on X that the agency is “coordinating and cooperating with the relevant agencies in relation to the missing scientists.

“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.”

Representatives from Caltech, which manages JPL, did not immediately respond to a request for comment.

The sun had barely risen over the Pacific Ocean when a small motorboat carrying a team of Indigenous artisans and Mexican biologists dropped anchor in a rocky cove near Bahías de Huatulco.

Mauro Habacuc Avendaño Luis, one of the craftsmen, was the first to wade to shore. With an agility belying his age, he struck out over the boulders exposed by low tide. Crouching on a slippery ledge pounded by surf, he reached inside a crevice between two rocks. There, lodged among the urchins, was a snail with a knobby gray shell the size of a walnut. The sight might not dazzle tourists who travel here to see humpback whales, but for Mr. Avendaño, 85, these drab little mollusks represent a way of life.

Marine snails in the genus Plicopurpura are sacred to the Mixtec people of Pinotepa de Don Luis, a small town in southwestern Oaxaca. Men like Mr. Avendaño have been sustainably “milking” them for radiant purple dye for at least 1,500 years. The color suffuses Mixtec textiles and spiritual beliefs. Called tixinda, it symbolizes fertility and death, as well as mythic ties between lunar cycles, women and the sea.

The future of these traditions — and the fate of the snails — are uncertain. The mollusks are subject to intense poaching pressure despite federal protections intended to protect them. Fishermen break them (and the other mollusks they eat) open and sell the meat to local restaurants. Tourists who comb the beaches pluck snails off the rocks and toss them aside.

A severe earthquake in 2020 thrust formerly submerged parts of their habitat above sea level, fatally tossing other mollusks in the snail’s food web to the air, and making once inaccessible places more available to poachers.

Decades ago, dense clusters of snails the size of doorknobs were easy to find, according to Mr. Avendaño. “Full of snails,” he said, sweeping a calloused, violet-stained hand across the coves. Now, most of the snails he finds are small, just over an inch, and yield only a few milliliters of dye.