Shocking new details have emerged concerning the mysterious disappearance and death of a New Mexico woman who worked at a secretive US nuclear lab.
Authorities have revealed that Melissa Casias, whose body was discovered on May 28, was shot in the head at or around the time of her death, but it remains unclear if this was murder or a suicide. Her body was found well after her death.
Casias, an administrative assistant at the Los Alamos National Laboratory, vanished without a trace on June 26, 2025 after strangely walking out of her home without any identification, keys or way of contacting her.
Her skeletal remains were discovered 11 months later in Carson National Forest, propped up against a tree with a handgun near the body.
The official autopsy noted that Casias had been shot through the base of the skull, with the bullet exiting through the left side of her head. However, the Office of the Medical Investigator could not say if this wound was what killed the 53-year-old.
Due to the amount of decomposition of Casias’s remains when she was found, the medical examiner could only say that the gunshot occurred ‘perimortem,’ meaning it took place around the time she died but may not have been the actual cause.
The medical examiner’s report added that the woman’s left hand and left leg were both found about 20 feet away from the body and showed signs of being attacked by wildlife who likely scavenged through the remains after death.
While the medical examiner could not tell if Casias’s death was a suicide or involved foul play, an anonymous law enforcement source told the Daily Mail the new details in the case point to murder.
Melissa Casias worked at the Los Alamos National Laboratory, a long-running nuclear research facility, before disappearing on June 26 last year. Her remains were found on May 28
The autopsy of Melissa Casias has been released and authorities have determined that the nuclear lab worker had been shot in the head
The newly released autopsy noted that the bullet was fired into the right side of Casias’s cranial base, hitting the bottom of the skull near the large hole where the spinal cord connects to the brain.
It also damaged the topmost neck bone, known as the C1 vertebra, before exiting through the left side of the head, through the flat, thin part of the temple.
‘There’s no way this was suicide, not from that angle,’ the law enforcement source claimed, noting the reported position of the bullet when it entered Casias’s skull.
The source believed that, if Casias was really holding the handgun at that angle, the gun would have recoiled, causing the bullet to change direction instead of passing straight through her skull.
‘The kickback would have made the gun go straight up. That’s ridiculous. She was murdered,’ the source alleged.
Officially, the medical examiner has labeled Casias’s cause of death as ‘undetermined,’ adding that the autopsy could not even determine how close the gun was to the nuclear lab worker’s head when it was fired.
New Mexico State Police told the Daily Mail that their investigation is still active, but did not reveal if investigators have interviewed any new suspects in the case.
Casias’ husband, Mark, was one of the last people to see his wife alive in 2025, when he was dropped off at LANL for work on the morning of her disappearance.
Melissa Casias (Left) pictured with her husband Mark Casias
Casias’s body was found alongside a handgun in the McGaffey Ridge area of Carson National Forest
Casias reportedly said she had forgotten her work badge needed to access the base at the couple’s Taos, New Mexico home.
Shortly after, she was seen bringing a sandwich to her daughter’s place of work, telling the teen that she would be working from home after forgetting the badge.
However, Casias never reported for work at LANL that day, with her family returning home to find a drop of blood inside the house and both of the wife and mother’s cellphones wiped and rebooted to their factory settings.
She was last seen on surveillance cameras walking alone eastward on State Road 518, roughly three miles from her home, around 2.20pm local time.
David Adams, a lawyer hired by Casias’s parents and siblings, previously told the Daily Mail the family has continued to suspect foul play after multiple red flags were raised by legal observers looking at the investigation into her disappearance and death.
Adams revealed in July that the woman’s relatives and other volunteers had unearthed a trove of evidence at the scene in Carson National Forest nearly a month after New Mexico State Police officially declared the crime scene clear and removed Casias’s remains.
The search team found bones, torn and bloody clothing, a tobacco pouch, orange peels and strands of someone or something else’s hair that were not collected by police when the 53-year-old’s body was recovered.
The discovery has turned the case on its head, with Adams claiming investigators in New Mexico have seriously damaged their credibility if it is found that Casias was the victim of foul play and a suspect is brought to trial.
‘There becomes a question of a chain of custody… Could law enforcement have spat a tobacco pouch in the crime scene? I mean, certainly possible. I mean, that would be an example of just poor training,’ Adams explained.
The medical investigator’s report determined that Melissa Casias was shot in the lower right-hand side of her skull, with the bullet exiting through the left temple
Casias was last seen walking alone in New Mexico after dropping off her husband at work at Los Alamos National Laboratory in June 2025, but not reporting for work herself
Casias’s work at LANL has raised fears that the administrative assistant may have been the target of a larger plot to steal classified government data on nuclear research or rocket technology.
Her disappearance has been linked to several other missing person cases in the Southwest, including a retired employee from LANL and former US Air Force General William Neil McCasland, who oversaw the military’s ties to research at the nuclear lab.
Overall, more than ten nuclear lab workers, NASA scientists and military personnel have been connected to the so-called ‘missing scientist’ case over the last year, with the White House ordering the FBI to investigate for any ties between the deaths and disappearances.
According to Adams, however, there have been no signs that the FBI has been looking into the death of Casias.
