I think most of the dead are his family members, except for the deputy. (William Durr, right, R.I.P.)
Narrative Collapse says it's the deadliest mass killing this year:
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It breaks the earlier 2017 mass killing record held by "Akron Man" below, who set an arson fire that killed seven:

Willie Corey Godbolt of Mississippi just shot eight people after a local deputy was called to a domestic dispute. (He blamed neighbors for calling the police.)