If you know what the *&%$ is going on, please let me know via a comment.
Homeland Security Police vehicles have been observed in America: Grand Junction Co and Brentwood TN that I know of.
26 October 2013, Grand Junction CO “So, as I was about to park, I saw this vehicle, so I quickly got out of my car and took a picture as it drove by. As the driver saw me do this, he slammed on the brakes, and asked, “Do you have a problem?”
“To which I replied, “Just taking a picture. Is that illegal now?” He then eked forward a few feet and stayed there in the middle of the road for about a minute and a half until a car approached him from behind, forcing him to move…
“This, ladies and gentlemen, is the FEDERAL POLICE FORCE (or Federal Protective Service, or United States Secret Service Uniformed Division as they are also known) we have been hearing about and the actual recipients of all that billions (yes, billions) of rounds of ammunition that is being produced for and procured by the Social Security Admin, The IRS, and other various government agencies for what purpose?
They are here, right in Downtown Grand Junction.
6 December 2013, Brentwood TN, from a relative.
“I PERSONALLY took this photograph in Brentwood, TN just 10 miles south of NASHVILLE, TN. This was on my way to work about three weeks ago. I was absolutely staggered that a Homeland Security Vehicle was not only present in the Nashville/Brentwood/Cool Springs area…but that the vehicle was emblazoned with the word “POLICE” on it. What in the world is going on here?
Again, if you know what is going on here, or if you know other sightings please comment. I am personally alarmed!
jawingjerry 
They have been here since the 20th Century. Relax. They used to be called Federal Protective Agents (Security Guards), but were bumped up under the Patriot Act to Federal Peace Officer Status. They guard the federal buildings and properties.