New Mexico State Police have confirmed that a handgun discovered near the skeletal remains of missing nuclear laboratory worker Melissa Casias was purchased by her husband, Mark Casias, who is an avid hunter. Casias, 53, vanished on June 26, 2025, and her remains were found approximately six miles from her Taos home on May 28, 2026, in a remote section of Carson National Forest.
An autopsy revealed Casias had been shot in the head, but medical investigators could not definitively determine if her death was a suicide or the result of foul play. State Police told the Daily Mail that the investigation remains active but did not disclose if any suspects have been named, if Mark Casias has been interviewed regarding the weapon, or if the handgun had been fired.
Casias' parents and siblings have publicly stated their disbelief that she would have taken her own life, citing irregularities at the scene where her remains were found. According to attorney David Adams, whom the family hired, evidence unearthed by relatives and volunteers included bloody clothing, bones, hair not belonging to Casias, and a tobacco pouch. Adams noted that Casias was not known to use tobacco.
Casias was last seen leaving her home on foot on June 26, 2025, after dropping her husband off at Los Alamos National Laboratory, where both were employed in non-scientific roles. She reportedly returned home for her security badge before delivering lunch to her daughter and was last spotted walking alone along State Road 518 around 2:20 p.m.
In a statement posted on Facebook on August 7, Casias' relatives asserted, "The Mondragon family AND Melissa's closest friends do not believe Melissa took her own life!" They emphasized her strong bond with her daughter, stating she would not willingly leave her behind. The family also indicated that the condition and circumstances of her remains discovery raised further questions.
Casias' daughter, Sierra, who is believed to be the last family member to see her alive, stated that she is not connected to the private investigation and pushed back against foul play narratives. In a statement reported by KOAT 7, she said the "undetermined" ruling does not assign responsibility and should not be used to create an unsupported narrative. Sierra Casias also noted that her mother was carrying a backpack when she disappeared, which was found near her body with a gun holster inside. A bottle of alcohol and potential notes were also found in the vicinity.
Sierra Casias previously maintained her mother did not own handguns or carry a weapon to work at the nuclear lab. She urged against speculation beyond the autopsy findings. However, the medical investigator's examination of Casias' skull showed a large exit wound on the left side and a suspected bullet trajectory traveling through the right side of her cranial base, damaging the C1 vertebra before exiting the left temple. The bullet has not been recovered.
This trajectory has raised doubts about suicide. An anonymous law enforcement source suggested the angle required for a self-inflicted gunshot would be implausible, indicating potential foul play. Despite these observations, New Mexico authorities officially state that severe decomposition prevented them from determining the manner of death or the distance of the gun from Casias' head when fired.
Former FBI agents have also questioned the circumstances, noting that both of Casias' phones were left at her home and had been wiped clean on the day she disappeared. Former FBI agent Ben Hansen told the Brian Entin Investigates podcast that the details shared are "highly, highly suspicious," leaning towards an 80% probability of foul play. Hansen also speculated about possible foreign adversary influence or that Casias may have been enticed under false pretenses, believing she would return.
Concerns have also been raised due to Casias' work at Los Alamos National Laboratory, a facility involved in nuclear research. Her disappearance has been linked to several other missing persons cases in the Southwest involving individuals connected to LANL, retired military personnel, and NASA scientists. The White House has reportedly directed the FBI to investigate potential ties between these cases, though attorney Adams stated there have been no visible signs of such an investigation into Casias' death.