Bag of pipe bombs sitting there? My guess is that some young guy, it's always a guy, found out how to make them and then realized "oh shit. I now have some fucking pipe bombs" and just dumped them. Of course it could be more serious than that, but after hearing enough late night booms around here I'm guessing it's just another dipshit experimenting.
http://www.bbc.com/news/world-us-canada-…