Where do you get this nonsense they didn't collect evidence? It was investigated like any other shooting death. If Zimmerman had prescriptions, that doesn't mean he was on those prescriptions at the time of the shooting. They didn't test Zimmerman for anything because he didn't display any signs of intoxication. He was interviewed by police for several hours at the station.
He blew away an unarmed black kid. Damned straight they should have tested him.
Ah, Ray, always has an excuse for white assholes who murder black children.