FBI agents showed up at the Sunspot solar observatory in tiny Sunspot, New Mexico, on Friday and shut down the facility, evacuating the local area, including the town post office.

“There was a Blackhawk helicopter, a bunch of people around antennas and work crews on towers, but nobody would tell us anything,” Otero County Sheriff Benny House told the Alamogordo Daily News. “I don’t know why the FBI would get involved so quick and not tell us anything.”

Five days later, the observatory’s website confirms the entire facility is closed to both staff and the public until further notice.