Anyone ever hear what happened with those swarms of drones running grid patterns over areas of Colorado a few months back?

I was watching a program last night on History channel. A guy who used to work for the governments ATIP program and now works for Academy to the Stars, said that the government tried to find out what the drones were, who they belonged to and where they came from.

Including the use of sophisticated recon aircraft and cameras. And came up empty. They also said the drones exhibited performance/flight times in excess of the most advanced drones known to be in use. Interesting, to me. Regards 18DAI