It does look like a flare gun with some kind of crazy homemade shell can kill. Whether the perp still has a hand is unknown.
http://www.fbi.gov/hq/lab/fsc/backissu/april2004/research/2004_02_research02.htm
Don't look unless you want to see a guy with a big hole in his head.
http://www.fbi.gov/hq/lab/fsc/backissu/april2004/research/2004_02_research02.htm
Figure 11 shows a wound caused by a flare gun that fired a homemade 12-gauge shotgun cartridge filled with screws, nuts, and other small metal objects.
Don't look unless you want to see a guy with a big hole in his head.