Seems this guy had a warped grudge with this church as one of his Ex's had attended it before. Even more strange was although he had obvious special training he used a shotgun holding just 3 shells. At first I thought the witness accounts may have missed hearing some of them but it was three shots. That's how they took him down because he was reloading and had about 70 more rounds. It was a sawed off too according to police press reports. That explains 6 hits most of them life threatening.
To bad it takes so long for justice to run it's course. This man will die of old age before facing what is likely to be his given sentence. The church may be liberal but this neck of the woods is majority Conservative.
Sawed off or just short? With a semi auto, at leas a gas operated one as most are (not all though) you can't saw it off too much or the action won't work. You'd be safe as long as you didn't cut it down shorter than the forward hand guard or magazine tube. The length of the barrel doesn't really affect the spread of the shot much, if any. It's the choke, or lack thereof, that does that. Most short barreled shotguns, even the most "legal" 18.5" barrels (like mine), have a 'cylinder' choke, which means no constriction at all, same as you'd get by sawing off the barrel. Even my 24" barreled 'bird gun', has a 'cylinder' choke tube available, although all I've got is 'improved cylinder', 'modified' and 'full', don't think I've ever used the 'full' though. The short one doesn't have interchangeable tubes so you are stuck with what it came with, but for 'serious social purposes', 'cylinder' is fine. OTOH, I once hunted with a guy who had a Remington 870 with an 18.5 or 20 inch barrel with interchangeable choke tubes, who used it for bird hunting, just by installing the appropriate tube. (OTOH, another hunter in the group asked him if he was going to shoot pheasants or rob a bank with it. IIRC, he shot pheasants with it, at least one. :) )