The discovery of a nuclear lab worker’s body nearly a year after she went missing has raised fresh questions in a mystery that has gripped America.
Melissa Casias, who vanished without a trace on June 26, 2025, was discovered in the McGaffey Ridge area of Carson National Forest, about six miles from the last place she was seen walking before being declared missing.
New Mexico State Police said Casias’s body was found alongside a handgun, but in a statement posted online last month, her daughter, Sierra, insisted the former Los Alamos employee did not own any guns.
‘She could not legally purchase a firearm and did not have one. Every firearm in our home is owned and purchased by my father. At no point did I EVER see her carry a handgun or keep one in her vehicle. She also spent the majority of her time working on Los Alamos National Laboratory property, where firearms are strictly prohibited,’ Sierra said in a Facebook post.
The discovery of Casias’ body has added a new layer of intrigue to the case because the area where she was found had reportedly been searched previously and has been the site of an ongoing US Forest Service restoration project since December 2025.
Chris Swecker, the former FBI assistant director in charge of the bureau’s Criminal Investigative Division, told the Daily Mail there are several critical questions investigators must now answer.
‘The gun that was nearby, was it a gun owned by her? What was her cause of death? Those are the first things you have to establish. Was this a suicide, or was this a crime?’ Swecker said.
The New Mexico State Police told the Daily Mail that investigators are still attempting to trace the gun’s origins, while the Office of the Medical Investigator is working to determine Casias’s cause and manner of death.
Melissa Casias worked at the Los Alamos National Laboratory, a long-running nuclear research facility, before disappearing on June 26, 2025
New Mexico State Police have stated that the body of Melissa Casias was found alongside a handgun in the McGaffey Ridge area of the Carson National Forest (Pictured)
Swecker added that the discovery may deepen concerns about a growing list of scientists, nuclear workers and national security personnel who have disappeared or died under unusual circumstances in recent years.
Casias, a wife and mother from Ranchos de Taos, worked as an administrative assistant at Los Alamos National Laboratory, the famed nuclear research facility that has been linked to America’s weapons programs since World War II.
Casias was an avid hunter and was photographed multiple times holding a rifle. However, the firearms Casias was seen carrying allegedly all belonged to her husband, as per her daughter’s May 5 statement.
Police have said that the cause and manner of Casias’s death have not yet been determined. She had been missing for 11 months before her body was found, however, the timing of her death has not yet been released by authorities. Her remains are undergoing further tests by the Office of the Medical Investigator.
Authorities noted that a hiker found the body on May 28, with investigators making a positive identification less than two days later. There are several ways to identify human remains. Visual identification is possible and easiest if the body is fresh and recently deceased.
Other common methods include fingerprints, dental records, and DNA testing, which can take anywhere from a few hours to several weeks, depending on the condition of the remains.
When asked whether the speed with which the positive ID came was surprising, Swecker said it was not entirely unusual, but if the body had really been in the forest for nearly a year, the harsh environment would have made identifying Casias extremely difficult by sight alone.
‘We don’t know what shape the body was in. It may, it could very easily have been a visual identification,’ he said.
The final image of Melissa Casias alive came from a surveillance camera near State Road 518 in New Mexico, approximately three miles from her home
Casias was an avid hunter and was seen carrying a rifle multiple times, but photos posted online did not show a handgun like the one police said was recovered near her body
Swecker noted that the area’s ‘animals and predators’ as well the region’s climate, humidity and temperature would have also worked against preserving Casias’s body for more than a few weeks.
Most of New Mexico and Carson National Forest is known for its populations of black bears, mountain lions, bobcats and coyotes – animals that may have found and consumed a body if it had been there for nearly a year.
According to Trauma Services, a professional biohazard remediation company, human bodies go through five basic stages of decomposition, mostly within the first two to three weeks after death.
After just ten to 25 days, Trauma Services said in a statement: ‘Most of the body mass has broken down, the bones, dried tissues, and residual fluids are all that’s left, and the rate of decay slows.’
If Casias had been dead in Carson National Forest for several months, the crime scene experts noted that only skeletal remains would have been discovered.
Casias was last seen walking alone in New Mexico after dropping off her husband at work at Los Alamos National Laboratory, but not reporting for work herself
Chris Swecker was a member of the FBI for 24 years. The counterintelligence expert warned that the disappearance of multiple people tied to national security fields was alarming
Casias’s family revealed that she left her home on foot without her work or personal phones, her identification, or her purse, which police said raised immediate concerns among her loved ones.
She was last seen walking alone eastward on State Road 518, roughly three miles from her home, with a small backpack, around 2.20pm local time.
Hours earlier, she had dropped off her husband, another LANL employee, at the facility, approximately 70 miles from their home.
That was when Casias’s behavior allegedly became unusual.
Her husband Mark said she claimed she had to return home after forgetting her badge for the lab.
Mark, a superintendent at the lab, found the statement strange because she would have needed the badge to get past the security checkpoints to drop him off.
When Casias arrived back in Ranchos de Taos, she reportedly visited her teen daughter, Sierra, at work to drop off a sandwich. Casias’s daughter told investigators her mother said she planned to work from home after forgetting the badge.
Melissa Casias (Left) pictured with her daughter, Sierra. Her daughter is believed to be the last family member is see Casias alive on June 26, 2025
Melissa Casias (Left) pictured with her husband Mark Casias
Private investigators have claimed without evidence that the death of Casias may have been a suicide, triggered by financial struggles
Despite what Casias reportedly told both her daughter and husband, she returned home to drop off her work and personal phones, which the family would later find inside the house, wiped clean after someone performed a factory reset to erase all calls and messages.
The woman’s family and private investigators have disputed how much access Casias really had to classified data, claiming that the LANL employee lost her security clearance due to financial troubles she and her husband were having.
Swecker said the presence of a gun at the scene after her unusual behavior suggested a possible suicide, but cautioned that it was still too early in the investigation to rule out foul play.
‘Given the publicity in this case, there are certainly investigators out there looking for some evidence of a crime,’ he revealed.
Swecker also referred to the multiple scientists, nuclear lab workers and retired Air Force general who have all died or disappeared under mysterious circumstances over the last few years.
He previously told the Daily Mail that he feared the growing list of names may be tied to a plot being carried out by a ‘hostile foreign intelligence service’ against US researchers and workers connected to advanced technology.
Casias’s disappearance and death was one of several to take place in New Mexico, alongside the disappearances of Anthony Chavez, a former LANL employee, and government contractor Steven Garcia, who worked at the Albuquerque facility for the Kansas City National Security Campus – a nuclear weapons lab.
‘I think there’s enough of a pattern, even if it’s a small group, I think there’s a smaller group of missing people that warrant an investigation by the FBI, which is the lead agency in counter-espionage, counterintelligence. I would be looking for that, unless we show something points to another direction,’ Swecker said.
