The sudden and previously unexplained evacuation of a New Mexico solar observatory on Sept. 6 was prompted by a child pornography investigation, according to Federal Bureau of Investigation documents.

An individual is suspected of "utilizing the wireless internet service of the National Solar Observatory in Sunspot, New Mexico, to download and distribute child pornography,” Reuters reported Wednesday, citing newly unsealed FBI records.

A laptop at the facility was seized without the knowledge of the suspect — a janitor, the Albuquerque Journal reported. The evacuation came after that person became increasingly agitated, prompting concerns about the safety of staff at the observatory, the publication reports.

In the wake of the evacuation and closure, officials provided little information, leading to widespread speculation and conspiracy theories. The observatory's proximity to Roswell — the site of an alleged UFO crash — helped fuel speculation, Reuters says.

The observatory reopened this week.

The Association of Universities for Research in Astronomy, the organization that oversees the observatory, reported Sunday that the site had been evacuated due to "law enforcement investigation of criminal activity" at Sacramento Peak, the mountaintop on which the observatory is located.

Authorities determined there was no risk to staff and that regular work could commence on Monday, the release stated.

The person being investigated has not been arrested or charged, Reuters reports.

Contributing: Dylan Taylor-Lehman, Alamogordo Daily News.