I added the rife part as it would be needed to penetrate bullet proof vests. My best guess, AK or SKS.
I've been following this all day. The police spokesman already said it was a handgun. No AK's or SKS's involved. Legal owners of military weapons have enough problems without adding crimes like this to the list!
A reasonable assumption, but just not correct. One might now assume that the perp/scumbag head shot them.