Posse Comitatus violation in Alabama?

The horrific killing spree in Samson, Alabama overwhelmed the local five-man police force, and prompted calls for help to surrounding departments. But police were not the only group to respond. The provost marshal, and 22 MPs from Ft. Rucker aided the town in crime scene control and traffic direction.

Unfortunately, the introduction of federal troops into civilian policing operations is expressly prohibited by law. The Army is investigating the situation, according to CNSNews.com.

The dangers of having military troops involved in policing activities is clear; it is something the American Republic has resisted since its foundation out of fears of what a standing army could do when used against its own civilian population. However, the use of 22 MPs to help a town struggling to meet the exigent demands of a mass murder, seems like the right thing to do. It would be unfortunate if doing the right thing ended someone’s military career, or worse, resulted in prosecution.
Update: AP moved a story on this, and it is appended below in comments section.
Update 2: A second AP story can be read below (or by clicking here). This updated story includes quotes from Gov. Riley’s spokesman.