Blanks typically contain wadding to hold the powder in place; this wadding is ejected from the gun and can, at short range, kill people. This has famously happened on several film sets before: https://en.wikipedia.org/wiki/Blank_(cartridge)#Safety
yes, but that is not the case here. Even if the gun was right next to the target when it went off, a blank would not penetrate the body, go through it, and enter another person like it did here. 2 people were stuck with this single "blank." Only something with the mass of a bullet can do that (unless there was a serious manufacturing defect, which is highly unlikely). I believe that is also where the term "point blank range" came from. A blank is generally not lethal unless it is fired at extremely close range, such as holding it to your head, like in the examples in that wikipedia article if you research the individual incidents.