You already talked to police, I understand? The only right thing to do. Sorry if this is sounding harsh, but backbreaker, you sounded like a whiny assed bytch to me... The guy didn´t see you, didnt´ see your car, you don´t know if it was a mafia or gang hit, you don´t even live there, you don´t have kids or a wife to worry about, and you´re making up all this bullshyt about potential threats to you.
A guy got shot, and it is your duty to talk to police, and in this situation where risk for you is minimal it is a must. If good men start looking the other way, society is going to hell for good, it has been said already.