While I am a member of the United Church of God, I have friends who attend the Living Church of God. I am not aware of any major doctrinal disputes in the Living Church of God. These murders appear to be the work of one man who was mentally ill.
TV report is that the shooter, Terry Razmann had just lost his job and may have been depressed.
It would be interesting to find out if the guy had recently been put on antidepressant medication.