While my personal choice would not be birdshot, this pattern indicates the shot was fired at greater than "in the house" distances. It also looks like he was fleeing the scene when shot.
Here's a not exactly real world video that one could use in an argument for using birdshot in a shotgun:
Around 9:40 or so he tests #8 in a 12 gauge for self defense to prevent over penetration in drywall.
My preference would still be buckshot, but at 5 yards the birdshot still seems to be pretty damaging. Sufficient for self defense? As he says "You be the judge".
Not necessarily. Most are used to seeing birdshot patterns when fired from our favorite hunting guns with 24”-28” barrels, and rarely an open cylinder choke.
Fire some of your favorite dove loads from a 14”-18” barrel with an open cylinder choke and see how quickly that pattern opens up. At distances found in many residences, it’ll look like the pic I posted above.
A shot in the back ain’t necessarily a “bad” shot from a legal perspective……perps don’t have to be facing you all the time, or even know that you’re there. It’s all based on the totality of the circumstances, and we don’t have nearly enough info to judge this shooting.