Relative to self defense, I think you were referring to Chai Vang, the convicted murderer. That claim came along very late, perhaps as late as his trial, and wasn't raised in his confession, where he indicated he was reacting to racial epithets. Other than the two or three hunters who initially confronted him for tresspassing, his other victims weren't armed and as I recall two were shot in the back. They had heard shots, and assuming a member of their party had taken a deer, hopped on atvs and went to the site unarmed, whereupon Vang opened fire on them. I believe there was a single shot fired by one of the initial armed victims. There were a two survivors, wounded, if I recall.
From your, and other freepers', sources, it does seem that that Vang did murder those men rather than defend himself.