According the to following Boston Globe article, a former marine picked up a downed officer's service weapon and shot the killer. Charges were not laid against the former marine.
http://www.boston.com/news/local/new..._deadly_in_nh/
I have two questions about this incident for CPers ...
One, are such acts of vigilantism justifiable, and two, would the marine have been charged with assault or illegal use of weapon or some such thing if this story had occurred in Canada?