I don't know if this latest and rather horrific incident could be considered part of an accelerating or long-term trend, as "on the rise" suggests. According to this timeline, 1997-2000 seem worse with more frequent shootings and a higher death toll than 2001-2005, although 2005 isn't over yet. It's not a formal crime survey, of course, so who knows what data might be missing.

The setting of a Native American reservation is interesting. I know similar reservations in Canada and Australia for indigenous peoples tend to score less favourably in social indicators, with higher rates of alcolholism and drug abuse, domestic violence, educational failure, teenage pregnancy, youth unemployment etc. than national averages (for whatever reason).

P.S. I don't know how I missed that HTML preview button before. Looks more like a tab to me, but it's real handy, regardless!