There's more detail on Blabbermouth. The known gist is: dude rushed the stage twice during a show, security got him, threw him back. He got up on the stage the 3rd time, past security, Randy shoved him off, fuckstick flew back, cracked his head and died.
We lost one of the best guitarists on the planet because some bag o' dicks jumped on stage and started shit. Randy would be in his rights to drop that fucker again if it was tomorrow.
I'd think bringing Dimebag's murder is probably not the worst tactic for the defense.