>>9120360 (PB)

Umm … maybe count the number of discharges?

As to why so many, 1) there are magazine fed shotguns (possibly in .410, which would explain having something to shoot AT after the 4th-5th discharge) or there could be more than one shotgun involved, possibly multiple shooters.

It would seem that he was still alive when the cops showed up, which argues that the shooter either didn't know what he was doing or deliberately chose small-sized shot.