A solar observatory shut down in mysterious circumstances "did not see aliens", its director has clarified.
But just why the National Solar Observatory in New Mexico was evacuated earlier this month remains a mystery, with the FBI still not telling local police why the research facility and a nearby post shop were closed.
"The FBI has not contacted us," Sgt Jon Emery of the Otero County Sheriff's Office told local news station KOB4.
"We don't know what they took, what their reason for being there was. We have no information on it."
Residents of the small town of Sunspot, where the observatory is based, have also been evacuated.
"It is very frustrating being out of our home," local man Sean Williams told KOB4. "I will say that and I can't wait until this is over."
A spokeswoman for the observatory on Friday (local time) said the directors have now made the call to keep it closed "until further notice due to an ongoing security concern".
Director James McAteer told KOB4 "nothing" will be kept secret once the "security concern" is over.
"[The] telescope did not see aliens. All data will be made public in its unaltered form."
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Conspiracy theorists earlier this week rushed to fill the information gap with wild theories of grand theft, energy weapons testing and experiments in defending against a solar flare that could cripple the world's electrical networks.
Sunspot is about 200km drive from the spot where a suspected UFO crashed in 1947. The official story is that it was a weather balloon.