I had not heard of this until today. Yesterday the Gov Hick signed a bill that effectively gave federal agents local jurisdiction in non-federal LE matters and crimes even when local LE isn't present. The bill states that it was
necessary for the immediate preservation of the public peace, health, and safety
http://www.leg.state.co.us/clics/cli...ile=013_01.pdf

The bill gives a special agent, uniform division officer, physical
security technician, physical security specialist, or special officer of the
United States secret service limited peace officer authority while working
in Colorado.
And it goes on to describe when and how.

I know sovereignty is not real popular in CO anymore but they just gave away any we had left.