The body of a missing nuclear lab worker has been found — alongside a gun — almost a year after she vanished without a trace, the latest in a string of disappearances and bizarre deaths involving experts and government employees working at some of the most secretive US national security facilities.
The remains of Melissa Casias, 54, who worked at the Los Alamos National Laboratory in New Mexico, were found in Carson National Forest over the weekend, some six miles from where she was last seen alive on June 26, 2025.
She was positively identified by New Mexico State Police on Monday.
A handgun was found alongside her body in the McGaffey Ridge area, although her exact cause of death and the date she is believed to have died have not yet been determined by authorities.
Her body was discovered by a hiker in an area where US Forest Service crews have been working regularly on a restoration project since December.
Casias worked as an administrative assistant at the lab, created during World War II for the famous Manhattan Project, and closely tied to US nuclear weapons research ever since.
On the day she disappeared, the married mother wiped all records from her phones before leaving them and her identification behind and walking out of her home in Ranchos de Taos, a remote community some 70 miles northeast of Santa Fe.
She dropped her husband, Mark, another Los Alamos employee, off at the facility before allegedly claiming she had forgotten her badge and had to return home.
The couple’s daughter, Sierra, told investigators that Casias dropped her off a sandwich and told her she planned to work from home after forgetting her badge.
Surveillance cameras last showed her walking alone eastward on State Road 518, some three miles from her home, at around 2:20 p.m. local time.
It is unclear if Casias owned a handgun, and New Mexico State Police are still examining the scene and tracing the gun’s origins.
Casias is one of four people who have gone missing or died suddenly in recent years with links to US defense and nuclear programs.
They include former Los Alamos employee Anthony Chavez, 79, who vanished without a trace after leaving his home on foot on May 4, 2025, just seven weeks before Casias.
Steven Garcia, a government contractor working for a major facility in Albuquerque, also disappeared after walking out of his home on Aug. 28, 2025, carrying only a handgun and no identification.
