Since mid-December, sheriff's departments in the border area of Nebraska, Colorado and Kansas have received at least 30 reports of night-time sightings of drone or drone-like objects flying in the sky in formations, sometimes in groups as large as 30.

As previously reported, the drones had a six-foot wingspan and were spotted around the same time each night between 7pm and 10pm before disappearing every night. Several citizens across the three states captured photos and video footage of the flying machines and posted them on social media, prompting the FBI, Federal Aviation Administration (FAA) and the US Air Force to launch an investigation into the mysterious sightings.

The FAA also reached out to unmanned aircraft systems (UAS) test sites, drone companies and companies authorized to operate drones in the area, but could not find anyone responsible for the swarms.

It has been weeks since the drone sightings were first reported and Transportation Secretary Elaine Chao has revealed that they still haven't figured out who is behind the swarms and have therefore decided to drop the investigation.

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