New Mexico State Police confirmed a handgun found beside missing nuclear laboratory worker Melissa Casias was purchased by her husband, Mark Casias.
State Police verified to the Daily Mail that the black Springfield handgun, bought by Mark Casias in 2020, was recovered near his wife's skeleton in Carson National Forest on May 28, 2026, nearly 11 months after she vanished.
The 53-year-old administrative assistant at Los Alamos National Laboratory disappeared on June 26, 2025. Her skeletal remains were discovered in a remote section of the forest known as the McGaffey Ridge area, approximately six miles from her home in Taos, New Mexico.
Los Alamos National Laboratory is a United States Department of Energy facility in northern New Mexico that conducts classified nuclear and defense research. Established during World War II, the institution is one of the premier scientific centers in the country. Casias worked at the facility alongside her husband, an avid hunter, as non-scientific administrative staff prior to her disappearance.
State Police confirmed that the investigation into her death remains active. Authorities did not state whether they have identified any suspects, whether Mark Casias has been interviewed about the weapon, or whether forensic testing indicates the handgun was fired.
Autopsy and Gunshot Findings
A newly released autopsy by the New Mexico Office of the Medical Investigator revealed that Casias suffered a gunshot wound to the head around the time of her death. Medical examiners ruled the manner of death as undetermined, stating that severe decomposition made it impossible to decide whether she died by suicide or foul play, or to determine how close the gun was to her head when fired.
Autopsy diagrams showed the suspected trajectory of the bullet believed to have killed Casias. The path traveled through the right side of her cranial base near the junction of her lower jaw and neck, damaged her C1 vertebra, the uppermost neck bone connecting the spine to the base of the skull, and exited through her left temple. The bullet has not been recovered.
An anonymous law enforcement source told the Daily Mail that the angle required for Casias to shoot herself in that manner was extremely implausible. "The kickback would have made the gun go straight up. That's ridiculous," the source claimed, arguing that the medical findings point to murder.
Disappearance Timeline and Physical Evidence
Casias was last seen alive on June 26, 2025, after dropping her husband off at Los Alamos National Laboratory. She returned to her Taos home after reportedly forgetting her security badge, delivered lunch to her daughter's workplace, and was last recorded on surveillance camera at 2:20 pm walking alone along State Road 518, roughly three miles from her home.
Following the police search, Casias' relatives and a team of volunteers examined the area where her body was found and gathered items left behind after authorities officially ruled the scene clear. Family attorney David Adams said this evidence included bloody clothing, bones, hair appearing to belong to someone other than Casias, and a tobacco pouch, noting that Casias was not known to use tobacco.
On August 7, relatives posted on Facebook: "We want to make something very clear: The Mondragon family AND Melissa's closest friends do not believe Melissa took her own life!" They continued: "Those who knew and loved Melissa know how deeply she loved her daughter. From the very beginning, her family has maintained that Melissa would not willingly leave her daughter behind, and they do not believe she would have ended her own life. The condition and circumstances in which Melissa's remains were ultimately discovered have only raised more questions for her family."
Casias' daughter, Sierra, believed to be the last family member to see her alive, issued a separate statement reported by KOAT 7 pushing back against claims of foul play. "The ruling of “undetermined” does not mean that anyone has been found responsible for my mother’s death, nor should it be used as an opportunity to create a narrative that the evidence does not establish," Sierra stated, adding that she is not connected to her relatives' private investigation.
Sierra disclosed that her mother was carrying a backpack when she vanished. Investigators located the backpack near her body containing a gun holster inside, while a bottle of alcohol and pieces of paper that could potentially be notes were found in the vicinity. Sierra had previously insisted her mother did not own handguns or carry weapons to her job at the nuclear lab, and she did not address the revelation regarding her father's Springfield handgun.
National Security Concerns and FBI Probes
Investigators also discovered that both of Casias' mobile phones were left behind in her home and had been completely wiped of all information on the day she vanished. Former FBI agent Ben Hansen told the Brian Entin Investigates podcast that the wiped phones and disappearance circumstances were "highly, highly suspicious," estimating an "80 percent foul play versus someone who's depressed" scenario and raising the possibility of foreign adversary influence or enticement.
Casias' administrative role at Los Alamos National Laboratory has raised fears that she may have been targeted in a plot to steal classified government data on nuclear research or rocket technology. Her disappearance has been linked to several other cases in the Southwest involving missing nuclear lab workers, NASA scientists, and military personnel, including a retired Los Alamos employee and former US Air Force General William Neil McCasland, who oversaw military ties to research at the nuclear lab.
While the White House previously ordered the FBI to investigate potential ties among more than ten deaths and disappearances connected to the missing scientist case, attorney Adams said there are no indications that federal agents have been looking into Casias' death. New Mexico State Police reported that their investigation remains active.
