On May 28, 2026, a hiker found the body of missing nuclear lab employee Melissa Mondragon Casias, 53, who was last seen alive on June 26, 2025.
New Mexico State Police (NMSP) said that her remains were discovered alongside a firearm in the McGaffey Ridge area of the Carson National Forest, off Rio Chiquito Road in New Mexico.
The Office of the Medical Investigator has yet to reveal the nature and cause of her passing, leaving her family without any answers.
Online conspiracy theorists have linked the mysterious circumstances of Melissa’s incident with a series of other missing persons cases involving individuals who worked at US research facilities and allegedly had access to sensitive information.
“I can’t grasp it, I don’t know, I can’t figure it out,” her husband, Mark, told local media.
Melissa Casias lied to her husband and daughter hours before vanishing
Image credits: Find Melissa Mondragon Casias/Facebook
Melissa Casias was an administrative assistant at the Los Alamos National Laboratory (LANL), a facility founded by the Manhattan Project, which developed the atomic weapon during the Second World War. The lab has since been tied to confidential nuclear research.
The day she disappeared, Melissa drove Mark, a LANL superintendent, to their office, located approximately 70 miles from their home in Ranchos de Taos.
She dropped him off around 6:15 a.m., said she had to drive to another location on the LANL premises for a task, and promised to return the car by 11 a.m. However, she drove back home instead.
Image credits: LiveNOW from FOX
When their daughter Sierra asked her why she was back, Melissa told her she would work from home that day as she had forgotten to carry her badge.
Mark told NBC Dateline in July 2025 that Melissa had her badge when she dropped him off: “You’ve got to show your badge to get in — and it’s always the driver. She showed her badge.”
Sierra told the outlet at the time that she had no reason to question her mother.
“Nothing was unusual,” Sierra said. “Her behavior wasn’t different. Nothing caught me off guard. Right when I was leaving [for work] — I always hug her goodbye, say, ‘I love you,’ all of that — We did that, that’s normal.”
Around 12:30 p.m., Melissa visited Sierra at the latter’s workplace, a John Dunn Shops outlet in Taos Plaza, and brought her a Subway sandwich. The two spoke for a few minutes, and Melissa left the location around 1 p.m., informing Sierra that she would be running some errands.
Melissa Casias had wiped both her phones before walking out of her home
Image credits: GoFundMe
It wasn’t until Mark received a phone call from Melissa’s boss, asking after her whereabouts, that anyone realized something was amiss.
Surveillance cameras last spotted Melissa around 2:20 p.m., walking alone southbound on NM State Road 518, roughly 3 miles from her home and 6 miles from where her body was recovered.
In the footage, she was wearing jeans, a white-and-turquoise t-shirt, a purple pullover tied around her waist, sneakers, and sunglasses.
Image credits: LiveNOW from FOX
When Sierra came home later in the day, she found her mother’s personal and work phones, along with her national identity cards and other personal items.
The phones had been wiped clean, with a factory reset performed on both devices.
It is unclear how long Melissa’s body remained in the forest before it was discovered. The area became part of a US Forest Service restoration project in December 2025, and crews have been working regularly in the region for the past 6 months.
Conspiracy theorists have linked Melissa’s case to several other missing or deceased US government employees
New Mexico and its history of nuclear research have given birth to many government lab-centric conspiracy theories ever since the first ever nuclear detonation was tested at the Trinity Site in Jornada del Muerto desert, all the way back in July 1945.
Melissa’s demise has been linked with three other New Mexico lab workers who have mysteriously disappeared under similar circumstances over the last year.
Image credits: Find Melissa Mondragon Casias/Facebook
Just seven weeks before Melissa went missing, Anthon Chavez, 79, a former LANL employee who retired in 2017, walked out of his home on May 4, 2025, and vanished without a trace.
Steven Garcia, 48, went missing on August 28, 2025, a month after Melissa, from his home in Albuquerque, New Mexico. He was last seen walking out of his home with a firearm and no other belongings or identification.
The Daily Mail reported that, according to an anonymous source, Garcia was a government contractor working for the Kansas City National Security Campus, a facility involved in critical background work in the USA’s national defense.
Image credits: KOB 4
On February 27, 2026, retired U.S. Air Force Major General William “Neil” McCasland, 68, disappeared from his Albuquerque, New Mexico home. He had been in charge of the Air Force Research Lab, which worked closely with projects involving the USA’s nuclear armory.
These cases have been further linked with more missing or deceased government personnel from other states, especially those associated with NASA’s Jet Propulsion Laboratory (JPL), such as Frank Maiwald and Carl Grillmair.
Image credits: LiveNOW from FOX
McCasland oversaw the government funding of Monica Reza, the director of the Materials Processing Group at NASA’s JPL and the inventor of Mondaloy, a space-age metal used in advanced missile and rocket engines.
Monica disappeared on June 22, 2025, while hiking with two friends near Mount Waterman in California’s Angeles National Forest.
He was also the senior supervisor of another deceased: Air Force Human Performance Wing research analyst, First Lieutenant Jaime Sue Gustitus.
An ex-FBI official previously expressed concern over potential connections between the cases
Image credits: Sierra Casias/Facebook
At the center of the conspiracy theory that connects these disappearances is the belief that multiple scientists, engineers, military researchers, and government-linked personnel were captured or assassinated.
The theories argue that they knew sensitive information about advanced technology, including secret energy programs, classified military projects, and even extraterrestrial beings.
Family members of several missing or deceased individuals mentioned in said theories have rejected the conspiracy claims, saying they have caused additional pain and misinformation.
Image credits: melissac0703/Instagram
However, former FBI Assistant Director Chris Swecker’s statements suggest the theories may have substance. He shared his concern with the Daily Mail in March 2026 that Melissa’s disappearance might be part of a much larger pattern.
Swecker insisted that Melissa’s work at LANL as an administrative assistant might have made her a target for abduction.
“In a classified lab, or just a high clearance lab, they would basically be in the know on what’s going on,” Swecker said. “’And it wouldn’t be the first time their administrative assistant has been targeted.”
“When I look at three missing scientists in critical technology areas, what I come up with is — it has to be investigated fully by the FBI. They can’t have these examined in isolation and compartmentalize them as individual missing person cases.”
“This is heartbreaking.” The internet mourned the tragic passing of Melissa Casias
