A national solar observatory in Sunspot, New Mexico is at the centre of an FBI investigation, prompting a frenzy of conspiracy theories. The observatory has been closed since last Thursday, when it was suddenly evacuated by FBI officials tasked with investigating an undisclosed "security issue". Government officials have refused to elaborate on what is behind the unexpected closure. The silence from officials has set off a range of theories, including a possible alien sighting, unexpected movement in the sun or a mercury leak.

Along with the Sunspot Solar Observatory, a local post office and around a dozen residents have been evacuated. Local county sheriff Benny House described blackhawk helicopters circling the area, as well as military figures working with antennas. Mr House said that the FBI has kept local residents in the dark, adding: "The FBI is refusing to tell us what’s going on. "What their purpose was nobody will say. But for the FBI to get involved that quick and be so secretive about it, there was a lot of stuff going on up there. "There was a Blackhawk helicopter, a bunch of people around antennas and work crews on towers but nobody would tell us anything."

For the FBI to get involved that quick and be so secretive about it, there was a lot of stuff going on up there Local county sheriff Benny House

Now scientists have spoken out about the mystery closure, insisting that the mysterious shutdown is not related to an extraterrestrial encounter. The team that operators the telescope at the observatory have confirmed there was no alien sighting. James McAteer, director of the observatory, did not reveal what exactly was behind the evacuation. He said: "The telescope did not see aliens. All data will be made public in its unaltered form. Nothing is hidden or kept secret."

The silence from officials has set off a range of theories, including a possible alien sighting