The report says ".. after the shooting residents said they saw two cars leaving the area at high speed."
This implies that the shooting occurred at the scene...but that isn't conclusive. Another factor is the load carried by the shotgun cartridges - these wounds don't look like pellets to me.
However - I agree entirely that the lack of blood is puzzling - given the nature of some of these wounds - even the body would usually have had more blood. But on the other hand - you can see the holes in the clothing and most are relatively blood free. So - suggests he died immediately and didn't bleed (unusual) - or he was already dead when some of the shotgun wounds were inflicted. Others more knowledgeable may wish to comment.