Missing scientist found dead after 11 months took two shocking items with her that cast doubt on suicide theory
The case of a missing nuclear lab employee who was found dead nearly a year after vanishing has taken a troubling turn, with new details raising questions about the suicide theory.
Melissa Casias, 53, a former administrative assistant at Los Alamos National Laboratory (LANL), disappeared from her home in Ranchos de Taos, New Mexico, on June 26, 2025.
Her skeletal remains, along with a reported gunshot wound to the head, were discovered in New Mexico’s Carson National Forest on May 28, lying next to a handgun that her family insists did not belong to the wife and mother.
Now, new details about her final moments have been released, revealing Casias took her toothbrush and thyroid medication before walking out the door of her Ranchos de Taos home for the last time.
Los Angeles Magazine contributor Lauren Conlin, who has been following Casias’ case closely and first reported on the items, told NewsNation that they are ‘things that might indicate you’re planning to stay alive.’
Morgan Wright, founder and CEO of the National Center for Open and Unsolved Cases, also said that there are key aspects of Casias’ disappearance and the discovery of her remains that do not add up.
‘You don’t get slumped up on a tree,’ said Wright.
‘Most of the time, in every crime scene I’ve worked on, there are skeletonized remains, and there’s no connective tissue left. Everything’s on the ground in pieces.’
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
Although Casias’ remains have been in the custody of authorities since June 1, the New Mexico Office of the Medical Investigator has yet to announce an official cause of death.
Earlier this month, authorities told the Daily Mail that an initial CT scan of the remains did not reveal any projectiles in the skull, meaning no bullet was recovered alongside the skull fragments found in the woods.
Police have not publicly confirmed that Casias suffered a gunshot wound to the head.
Those details were first disclosed to the Daily Mail by Arizona-based investigator Thomas McNally, who had been working on the case on behalf of Casias’ parents, Joe and Joanne Mondragon.
The absence of a recovered bullet has raised questions among independent investigators.
Wright said the type of ammunition allegedly used could be a key factor, telling NewsNation that some bullets expand upon impact and are often recovered from a body, while others are more likely to pass completely through.
He argued that determining the type of ammunition involved could help investigators understand why no projectile was found.
Casias vanished after dropping off her husband, Mark, another LANL employee, at the facility that morning, approximately 70 miles from their home.
Melissa Casias worked at the Los Alamos National Laboratory, a long-running nuclear research facility, before disappearing on June 26, 2025
Melissa Casias (Left) pictured with her husband Mark Casias
She then claimed she had to return home after forgetting the badge needed to access the nuclear lab.
According to Mark, Casias had the security badge with her when she dropped him off that morning, as she would have needed the badge to get past the security checkpoints to drop him off.
When Casias arrived in Ranchos de Taos, the couple’s daughter, Sierra, reportedly told investigators that her mother visited the teen’s place of work to drop off a sandwich and then said she planned to work from home after forgetting the badge.
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 of all data.
Surveillance cameras last spotted Casias walking alone eastward on State Road 518, roughly three miles from her home around 2.20pm local time.
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
Former FBI Assistant Director Chris Swecker told the Daily Mail in March he was concerned her disappearance was part of a much larger pattern involving individuals who had access to top secret government research.
Swecker explained that Casias’s work at LANL may have made her a target for abduction, since an administrative assistant often has access to the same sensitive files their supervisors have.
‘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.’
However, the woman’s family and private investigators have disputed how much access Casias really had, claiming that the LANL employee lost her security clearance due to financial troubles she and her husband were having.
