License to Maim

Why was the death-to-injury ratio so low in Boston? Because the terrorists wanted it that way:

The explosives that killed three people and injured more than 170 during the Boston Marathon on Monday were most likely rudimentary devices made from ordinary kitchen pressure cookers, except they were rigged to shoot sharp bits of shrapnel into anyone within reach of their blast and maim them severely, law enforcement officials said Tuesday.

It takes a fiendish kind of sadism to come up with the idea of ripping the legs off of runners, and then to figure out the exact best way to do it.