Groups of drones have been spotted buzzing over rural parts of northeastern Colorado and western Nebraska for weeks, unnerving residents. Now, U.S. officials are working with state and local authorities to determine who is behind the mysterious nighttime flights.
Morgan County Sheriff David Martin hosted a closed-door meeting with law enforcement agencies and government officials Monday to talk about the recent sightings.
The drones reportedly have 6-foot (2-meter) wingspans and fly in grid-like patterns hundreds of feet in the air in groups of six to 10. The Federal Aviation Administration, the Drug Enforcement Administration, the Air Force, and the U.S. Army Forces Command have said they do not have information about the aircraft.
"We take every drone-sighting report seriously," the FAA said in a statement after Monday's meeting. "Multiple FAA divisions are working closely with federal, state and local stakeholders to try to determine whether the reported sightings in Colorado and Nebraska are drones and, if so, who is operating them and for what reason."
The FAA said it has contacted drone test site operators and drone companies but has not determined if they were behind the flights. The agency also has been in touch with several airports in the area, warning pilots to be cautious and asking them to report any sightings.
Sheriff's officials say it appears that no laws are being broken. Drone pilots are not required to file flight plans unless they are in controlled airspaces, such as near an airport.
Phillips County Sheriff Thomas Elliott told The Denver Post in December that the drones remain about 200 to 300 feet (61 to 91 meters) in the air and fly steadily in square patterns of about 25 miles (40 kilometers).
"They've been doing a grid search, a grid pattern," he said. "They fly one square and then they fly another square."
Authorities in several Colorado counties have been getting calls about the devices.
Martin, the sheriff in Morgan County, Colorado, did not respond to a request seeking comment about the meeting.