Melissa Mondragon Casias, 53, disappeared from Taos County, New Mexico on June 26, 2025. Nearly a year later, her remains were found in Carson National Forest. How she died is still unknown.
Melissa worked as an administrative assistant at Los Alamos National Laboratory, alongside her husband, Mark. On the morning of June 26, 2025, she dropped Mark off at work and later brought lunch to her daughter, Sierra, in Taos Plaza. That afternoon, she was seen on doorbell camera footage walking along State Road 518 near her home in Talpa. She never returned. Her wallet, keys, and both cellphones — wiped of data — were later found inside her locked home, with her car still parked outside.
On May 28, 2026, a hiker discovered skeletonized human remains in the McGaffey Ridge area of Carson National Forest, about six miles from Melissa's home. New Mexico State Police confirmed the remains were hers. A handgun was also found near the site. The Office of the Medical Investigator has not yet determined how or when Melissa died, and an early forensic scan did not find a projectile in her skull, though investigators say that finding alone doesn't rule out the firearm's involvement.
Melissa's family, particularly her niece Jazmin McMillen, has said publicly that early theories she left voluntarily may have slowed the investigation's urgency. The family has since hired independent investigators and a law firm, Parnall and Adams, to review the case alongside law enforcement. A search organized by Melissa's paternal family, the Mondragons, later recovered hair, clothing, additional bones, and torn paper at the site — after law enforcement had already released the scene.
Melissa was the second Los Alamos National Laboratory employee to go missing in 2025, following the disappearance of 78-year-old Anthony Chavez that May. Law enforcement has told reporters that at least ten missing or deceased employees connected to sensitive national laboratories are part of a broader pattern the FBI is now investigating for possible connections.
Melissa's family has never accepted the idea that she simply walked away from her life. If you have any information about what happened to her, please come forward.
How to report a tip:
New Mexico State Police: 505-827-9300