This seems more like a criminal hit than an international terrorist attackThe reason I shy away from that theory is that this guy was just a (very) high level bureaucrat. Decisions about prisoners are generally made by others. One thing he was directly involved in, however, were some painful decision about prison closings, which can have a big effect on a small town's economy.
There's a story breaking now that the driver of a car matching the description of one seen outside the victim's house (black Cadillac, Colorado plates) was involved in a high speed chase and gun battle in Texas when police tried to pull him over. He's basically on life support now and the cops aren't releasing his identity yet.
Driver in Texas Shootout Possibly Linked to Colorado Prison Chief Murder