FBI Investigating Deaths & Disappearances of Scientists for Possible Connection

There have been several deaths and disappearances of scientists and government workers in the past few years ... and now the FBI is looking into whether or not these cases are linked, NBC News reports.

The House Oversight Committee announced Monday they're wondering if there's a possible connection between at least 10 people who have died or gone missing since 2023.

The Committee says two of them are linked to Los Alamos National Laboratory, and two of them are affiliated with NASA's Jet Propulsion Laboratory.

And multiple disappearances involve the person in question leaving their phones behind.

These high-profile cases have even reached President Donald Trump, who told reporters Thursday it's "pretty serious stuff … hopefully a coincidence, or whatever you want to call it."

The president said we'll know in the next week and a half whether or not it's random.

But for now, we're breaking down each mysterious case.

Air Force Major General William "Neil" McCasland was reported missing by his wife, Susan McCasland Wilkerson, after he vanished from his home in Albuquerque, NM on February 27, 2026.

Neil spent his final two years in the USAF as a commander at Wright-Patterson Air Force Base in Ohio, which many people believe contains evidence of aliens from a mysterious 1947 crash in Roswell, NM.

In the 911 call reporting his disappearance, Susan told the dispatcher she had "some indication that he planned not to be found."

Police say he left his phone and glasses at home, and the Bernalillo County Sheriff's Office reported a .38-caliber revolver was missing ... along with his hiking boots and wallet.

Steven Garcia was reported missing on August 28, 2025, last seen in Albuquerque, NM, wearing a green camo shirt and glasses.

According to a flier posted to the ALERT NEW MEXICO Facebook Group, he left his home with a handgun and "may be a danger to himself."

The Hill reports Steven was a property custodian with top security clearance at Kansas City National Security Campus, which manufactures "80 percent of non-nuclear components that go into the nuclear stockpile," according to the KCNSC website.

Monica Jacinto Reza went missing on June 22, 2025 while hiking in the Mount Waterman area of the San Gabriel Mountains in California, according to the Crescenta Valley Sheriff's Station.

According to SpaceNews, Monica is a scientist who, in the '90s, helped invent a "nickel-based superalloy" called Mondaloy to be used in rocket engines. The article notes she was working at Aerojet Rocketdyne at the time.

The press release from the House Oversight Committee on Monday said she worked as the director of NASA Lab's Materials Processing Group, and had previously worked at the NASA Jet Propulsion Laboratory.

The New York Post reports the Los Angeles County Sheriff's Department searched for months, but never found her.

Melissa Casias went missing on June 26, 2025. Her husband, Mark, told Dateline she dropped him off at the Los Alamos National Laboratory in New Mexico, where they both worked.

Their daughter, Sierra, told "Dateline" she heard her mom return home a little after 7:30 AM. When Sierra asked what she was doing back, Melissa said she had forgotten her badge, but ultimately told her daughter she was going to "either work from home or call out for the day."

Sierra then went to work at a cafe -- noting her mom brought her a sandwich a little before 1 PM ... and police confirmed they spoke then. She said her mom's behavior "wasn't out of the ordinary" ... but that was the last time she saw her.

Meanwhile, Mark told "Dateline" he got a concerned call from Melissa's boss ... who said she wasn't at work. When he was reportedly unable to reach his wife, Mark asked Sierra to contact her ... since they'd spoken recently.

Sierra says she texted her mom and the message was delivered, telling "Dateline" ... "I assumed that she was just gonna call him."

New Mexico State Police PIO Sergeant Ricardo Breceda told "Dateline" Melissa was last seen around 2:18 PM, when an acquaintance saw her walking along the NM 518 state highway ... which was also captured on nearby surveillance cameras.

According to "Dateline" ... Mark started frantically calling Sierra around that time because he still hadn't heard from Melissa. Sierra told "Dateline" when she texted her mom again, the message didn't deliver.

When she got home later that afternoon, Sierra told "Dateline" Melissa had left her keys and work phone on the kitchen table.

According to her LinkedIn ... Melissa had been an administrative assistant at LANL since March 2023. The lab "addresses national security challenges by advancing breakthroughs in science and technology" ... according to its website.

Mark told "Dateline" he "can’t grasp" Melissa's disappearance, saying ... "I don’t know. I can’t figure it out."

Anthony Chavez also worked at the Los Alamos National Laboratory in New Mexico -- multiple outlets report -- and vanished just a month before Casias did.

According to the Los Alamos County Police Department, Anthony was reported missing on May 8, 2025.

In a Facebook post ... the LACPD said he is "not believed to be endangered," but his friends and family say his disappearance is "out of character."

It's unclear what Anthony's job at LANL entailed.

Frank Maiwald -- a scientist with experience in space research -- died on July 4, 2024 at the age of 61, according to his obituary.

The memorial says Frank spent years at JPL managing the development and delivery of several NASA instruments -- the SBG-VSWIR instrument and instruments for the AMR-C program.

According to the obit ... Frank worked on a bunch of other projects and has won multiple JPL and NASA awards.

There's no mention of his cause of death.

MIT professor Nuno Loureiro was shot in his home in Brookline, MA on December 17, 2025, and died at the hospital the following morning ... according to CBS News.

In an obituary, MIT confirmed Nuno was a professor of nuclear science and engineering, as well as a professor of physics.

MIT says Nuno was a "lauded theoretical physicist and fusion scientist," and his research "addressed complex problems lurking at the center of fusion vacuum chambers and at the edges of the universe."

According to CBS News, the suspect in Nuno's murder was identified as Claudio Manuel Neves Valente ... who had opened fire at Brown University just days before.

CBS News reports Valente was found dead in New Hampshire later that week ... and had died after shooting himself in the head, according to his autopsy.

No word on what his motive was.

Scientist Carl Grillmair was shot and killed on February 16, 2026 on his porch in Llano, CA in Antelope Valley ... according to Pasadena Now.

In an obituary, CalTech confirmed Carl was an astronomer for their Infrared Processing & Analysis Center. According to its website ... IPAC works closely with NASA and JPL to "advance exploration of our Universe."

Pasadena Now reports 29-year-old Freddy Snyder was charged with the murder and is set to be arraigned April 29.

No motive has been published.

The body of Jason Thomas -- who worked for the Novartis biomedical research institute -- was found in a Massachusetts lake on March 17, 2026 ... three months after he had been reported missing.

According to a news release from the Middlesex County District Attorney's Office, Jason's wife reported him missing to Wakefield Police on December 13, 2025 ... because he didn't come home the night before.

Jason was a senior investigator with Novartis, according to his Linkedin profile.

The D.A.'s office says in the release that the medical examiner hasn't determined cause of death yet ... but authorities are ruling out foul play.

Scientist Michael David Hicks died on July 30, 2023 ... according to an obituary written by the American Astronomical Society.

The memorial says Michael was 59 years old and living in Sunland, in L.A., at the time. It says Michael worked as a research scientist with JPL, where he worked on projects about asteroids and deep space.