Without some concrete physical evidence proving the owner a liar I would be inclined to believe that the squatters cuased him to fear for his person. I would also find that fear reasonable unless the squatters were fleeing in the opposite direction, which by the survivors account they were not. Given only the facts presented in the article (two druggie squatters are roused and make furtive movements towards the property owner) I would not convict.
If "furtive" movements justify a homicide and another wounded in your mind, then who am I to argue.......