That's just never happened. I remember people saying the same thing about the murder committed by Luigi Mangione, before he was identified.
This was sloppy as hell.
He was either aiming for his head and shot low, or aiming for his chest and shot high. He left a palm print, shoe prints, and almost certainly his DNA. He dumped the gun like an amateur, leaving behind a goldmine for investigators.
I agree on the timing regarding an arrest, but I'm convinced this is going to be a lone wolf with his own grievance.