Possible, but the range *does* have skeet-shooting, and it's not unreasonable to think that some skeet shooter at the range accidentally got a slug round mixed in among his skeet loads, or had one left in the chamber/magazine that he had forgotten about.
The slug missed Good, but hit his house. Hmmm. There is a long standing dispute with the new homowners wanting to close the range down. Double hmmm. Gun control advocates always lie. Triple hmmm. Most skeet shooters I know never buy slugs because they never shoot them at anything. Some are seriously into reloading because their sport burns up a lot of rounds, but just with shot. Quadruple hmmm.