For weeks, mysterious unidentified flying objects over the Eastern Plains region of Colorado have vexed residents, law enforcement, the military, and state and federal officials.

Those who see them say they appear in the night sky, often several at a time, their locations marked by the light they emit. Audibly buzzing, they hover and maneuver in precise formations.

The mystery of their origin has gripped Colorado, where news of a sighting makes near-daily headlines and no one has yet copped to operating the aircraft. The state’s governor, Jared Polis, deployed the state plane to hunt them down after a pilot believed one of the objects came too close to a Flight for Life helicopter. And a constellation of government agencies has formed a task force to get to the bottom of the mystery.

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Representatives from some 77 agencies, including the military and the FBI, met for a closed-door briefing in the small town of Brush on Jan. 6.

“The group is not going to discuss the details of its inner workings, and is not planning to provide incremental updates on its activities,” Ian Gregor, a Federal Aviation Administration spokesperson based in Los Angeles, told The Daily Beast. “But we will inform the public about any important developments.”

The FAA has reached out to UAS test sites, drone companies, and companies that have authorization to operate drones in the area, “but we have not been able to determine that any of these operators were the source of the reported drone flights,” an FAA statement read.

In the vacuum of any definitive answer about who might be responsible for the aircraft, theories have ricocheted around the internet. Media have been drawn to small towns on the Colorado-Nebraska border. A storm chaser crew is on the case.

Some observers believe the UFOs could be alien visitors. Other locals say what they’ve been seeing are merely quadcopter-style drones.

“There’s nothing about these sightings that’s inconsistent with drone technologies, so why reach for the most extreme explanation?” Seth Shostak, an astronomer with the SETI Institute in California, which uses powerful sensors to search for aliens, told The Daily Beast.

“Besides, everyone knows that the alien spacecraft prefer the American Southwest,” Shostake joked. “Must be the Tex-Mex cuisine.”

Read more: The Daily Beast