A retired Air Force general known in UFO circles has gone missing during a hike in New Mexico, just months after a former colleague disappeared in a nearly identical case.
US Major General William Neil McCasland, 68, was last seen on the morning of February 27 as he left his Albuquerque home with only a backpack, wallet and .38-caliber revolver for a trail run, according to the Bernalillo County Sheriff's Office.
His mysterious disappearance came just six days after President Donald Trump pledged to release long-awaited files on UFOs and extraterrestrial life.
Sources previously told The New York Post that McCasland was a 'gatekeeper' and 'participant' in the UFO community.
His disappearance has only fueled speculation around the disappearance of 60-year-old Monica Reza, who had worked on a rocket project overseen by McCasland, who also went missing in June 2025.
In a chillingly similar case, Reza was last seen hiking in a California forest with a colleague, smiling and waving moments before she 'vanished off the face of the earth,' according to NewsNation.
For months, authorities and volunteers have combed the area using every resource at their disposal, but the aerospace engineer remains missing without a trace.
At a recent press conference, Sheriff John Allen said a Silver Alert was issued for McCasland after reports of a 'mental fog' in the months before his disappearance, adding that he had no other known health problems.
Months before, 60-year-old Monica Reza (pictured), who had worked on a rocket project overseen by McCasland as an aerospace scientist, also went missing during a hike
McCasland's disappearance came days after President Trump pledged to release files on UFOs and extraterrestrial life
Yet despite an intensive search involving drones, helicopters, ground crews and K-9 units, the avid outdoorsman - and any trace of his belongings - also remains missing.
'Let me be straight. We've had a lot of tips, and we will go through every tip. But there are some tips with some outlandish theories, conspiracy theories,' the sheriff said.
'We will look into everything, but we are trying as a law enforcement agency and entity,' he added.
The general's wife, Susan McCasland, posted on Facebook to set the record straight amid what she described as 'misinformation' about her husband's disappearance.
'It is true that Neil had a brief association with the UFO community,' she wrote. 'This connection is not a reason for someone to abduct Neil.
'Though at this point with absolutely no sign of him, maybe the best hypothesis is that aliens beamed him up to the mothership. However, no sightings of a mothership hovering above the Sandia Mountains have been reported.'
Just nine months ago, Reza - known professionally as Monica Jacinto at Aerojet Rocketdyne as a material scientist - was last seen hiking on the popular Mount Waterman Trail in the Angeles National Forest in Los Angeles.
Like McCasland, she loved hiking. She was just 30ft behind the man she was with when she vanished on what was described as a 'normal day,' according to NewsNation.
McCasland was reportedly a 'gatekeeper' and 'participant' in the UFO community (stock)
McCasland's wife Susan (both pictured) shared that her husband's UFO ties 'is not a reason for someone to abduct Neil'
In June 2025, Reza (pictured) was hiking 30 feet behind a companion on a Los Angeles trail when she 'vanished off the face of the earth'
'He turned around, next thing you know, she was just completely gone,' the outlet reported.
'Rescue teams spent days looking for her, but actually never recovered her body.'
Reza worked for Aerojet Rocketdyne, a high-profile company funded for years by NASA and the Air Force Research Laboratory, according to SpaceNews.
In the 1990s, she engineered a nickel-based superalloy that could survive extreme oxygen environments without added weight - technology that helped create the AR1 engine, set to replace Russian RD-180 engines on United Launch Alliance rockets.
Her patented invention brought her into McCasland's sphere, as he oversaw the Air Force group that funded early-2000s research on advanced materials for reusable spacecraft and weapons systems.
McCasland's Air Force biography reveals he oversaw advanced materials as director of the Space Vehicle Directorate's materials wing and commanded the Phillips Research Site at Kirtland Air Force Base from 2001 to 2004.
His roles ultimately had a direct connection to Reza's highly successful research.
The general had also led research at Ohio's Wright-Patterson Air Force Base, which Marik Von Rennenkampff, a former Obama-era national security analyst, described as 'where all the super-secret research happens,' CNN reported.
On the day he vanished, McCasland spoke with a repair person at his home at 10am, while his wife left around an hour later for a medical appointment, the sheriff's office said.
She returned at noon to find her husband gone, though his phone, prescription glasses and smartwatch were still there.
'His wearable devices and taking his phone were common practice with him. That is out of the norm,' Deputy Kyle Woods said during a press conference.
The sheriff revealed that authorities had gone door to door at 700 homes, including those near his Quail Run Court residence, trying to find him.
Search teams combed the areas McCasland often hiked, including Elena Gallegos and Domingo Baca Canyon, with dogs and horse units investigating mysterious odors.
Days later, authorities discovered a US Air Force sweatshirt about a mile and a half from his home. While it hasn't been confirmed as McCasland's, no blood was found on it.
Lt Woods said there has been no indication of foul play, nor any evidence from his electronic devices suggesting unusual circumstances.
Authorities mentioned McCasland’s reported ‘mental fog’ but added that they would not provide further details regarding any mental health issues.
Sheriff John Allen said a Silver Alert was issued for McCasland (pictured) after reports of a 'mental fog' in the months before
McCasland (pictured) disappeared without his phone, prescription glasses and smartwatch
This photo shared on Facebook was taken of Reza in the hours before she went missing
'There's no indication, and we are not putting forward that Mr McCasland was disoriented or confused,' Woods said.
'Arguably, he would still be the most intelligent person in the room that any of us would be in. Highly intelligent, highly capable,' he added.
Still, the deputy acknowledged the grim reality: 'We are many weeks in, and if he were to have gone into the mountains, the likelihood of surviving this time frame would be very low.'
Police said they are chasing every lead but warned that countless 'rabbit holes' have made their work far more challenging.
The overlap in timing combined with the bizarrely similar details of both cases has ignited a storm of online theories trying to connect them.
Investigative journalist Ross Coulthart described McCasland as 'a man with some of the most sensitive secrets of the United States head,' according to an interview on NewsNation.
'The timing is screechingly relevant,' he said. 'The fact that General Neil McCasland has disappeared off the face of the earth is a grave national security crisis for the United States of America.'
But the sheriff's office has maintained that there is no evidence of criminal activity, including kidnapping.
Investigative journalist Ross Coulthart described McCasland (pictured) as 'a man with some of the most sensitive secrets of the United States head'
McCasland's wife (both pictured) said her husband worked in the UFO community after retirement, offering unpaid expertise on military, technical and scientific matters
Retired FBI agent Jennifer Coffindaffer shared on X that she suspects McCasland (pictured) may have died by suicide
'Not that I believe the premise, but what I do believe is that likely, General McCasland took his life,' Coffindaffer wrote.
'He retired over a decade ago,' she added. 'I don't believe his military background has anything to do with his disappearance. His health may have. We don't know his medical condition, but was it grievous?'