If someone was shooting at you wouldn't shoot back?
(1) He claims he was shot at. The other witnesses contradict his story.
(2) If he were shot at, then he had a right to shoot back at the person who was threatening his life. He had no "right" to slaughter the other five unarmed people. Shooting a woman who was trying to help her wounded father is particularly vile.
(3) If he was trespassing on someone's property and he made threatening comments to them when asked to leave, as is attested by witnesses, then he had no right to anything other than to hightail it out of there.