How can there not be an identified suspect?
Immediately, I think most would believe that this is an intrafamily dispute gone postal. Everybody in the family knew about the dispute, but never thought he would take it this far. So the suspect is immediately known, and is the subject of a massive manhunt. Last bullet shot is usually the one the perpetrator saved for himself, either voluntarily, or as the police close in.
24 hours later, no suspect, no manhunt, not even a "person of interest." Given the style of the killing and the area we are talking about, could this be a gangland-style killing carried out by a rival in the drug trade? A real Walter White just made his play?
Regardless, with 8 people dead, local and state law enforcement have immense motivation to identify and apprehend the perpetrator ASAFP.