The Case of the Mysterious Colorado Drones keeps getting murkier.

Over Christmas, Colorado police reported at least 17 fixed-wing drones with a six-foot wingspan flying what appeared to be a steady pattern over several northeastern counties.

Earlier this week, the nightly drone sightings expanded to more Colorado counties as well as neighboring Nebraska. Most reports state the drones are flying between 7-10 p.m. at an altitude of 200-300 feet with speeds estimated at 25-40 mph.

The mystery broadened yesterday as residents on the outskirts of metro Denver reported drone sightings across Castle Rock, Parker and Fort Collins.

On Monday, a multi-agency task force formed to further probe the sightings. The group comprises representatives from more than 70 local, state, federal and military agencies including 10-15 law enforcement agencies as well as the FBI and FAA.

“We’re taking every report we get seriously,” FAA spokesperson Ian Gregor stated in a press conference. After contacting several possible leads, Gregor said the FAA has been “unable to determine that any of these entities was the source of these reported flights.”

“The purpose of today’s meeting was for the various agencies to share information and to discuss how we can most effectively collaborate in our efforts,” the FAA added in a statement.

The Phillips County (Colo.) Sheriff’s Office thinks the drones may be controlled from a mobile station. An official Facebook post states: “We are looking for the command vehicle. We are looking for a closed box trailer with antennas or a large van that does not belong in the area.”

Theories run rampant and a Colorado military journalist thinks he may have the most plausible answer.

“The answer could be a secretive Air Force program intended to keep prying eyes away from nuclear missile silos,” writes Tom Roeder, Senior Military Editor with the Colorado Springs Gazette.

Roeder adds:

“Air Force Global Strike Command, which is based in Louisiana, has confirmed that it conducts counter-drone exercises out of F.E. Warren Air Force Base in Cheyenne, where it is based. [An FAA] map of the region where the drones have been spotted — Logan, Phillips, Sedgwick and Yuma counties — is pocked with red dots of where drones are forbidden, restricted airspace presumably above missile silos.”

Roeder added the Air Force is neither confirming nor denying the possible scenario. However, he stated counter-drone firm Dedrone contracted with F.E. Warren in 2017. A Dedrone sales representative told Roeder the Air Force is “fond of testing F.E. Warren’s drone-detecting capabilities.”