This Colorado incident appears to be similar to a recent incident involving motorcycle clubs like the recent incident in Waco,TX.So far no federal agency involvement acknowledged.

More: Most people involved in Denver Coliseum shooting were in a motorcycle club of some kind, Denver police chief says - @KyleHoranNews

Person of interest being interviewed, but no arrests made following shootings, stabbing at Denver motorcycle expo, police say; shooting was 'exchange' of gunfire

Denver Coliseum shootings, Jan. 30, 2016
Denver police say incident at motorcycle show left 4 people shot, 1 person stabbed, and 3 people with lesser injuries; Sunday's event at National Western Complex cancelled - @CBS4Jeff