782.11 Unnecessary killing to prevent unlawful act.
Whoever shall unnecessarily kill another, either while resisting an attempt by such other person to commit any felony, or to do any other unlawful act, or after such attempt shall have failed, shall be deemed guilty of manslaughter, a felony of the second degree, punishable as provided in s. 775.082, s. 775.083, or s. 775.084.
Officer Smith wrote that when Zimmerman was being attended to by the Sanford Fire Department that he was yelling that he wanted help, and that no one would help him. Smith then writes "At no time did I question Zimmerman about the incident that had taken place."
Now why would he write that? Because at this point in time, Zimmerman was a SUSPECT of a second degree felony, he was handcuffed, and was placed in a police vehicle. If Smith had talked to him without reading him his Miranda rights, Zimmerman's statements would have been suppressed, and quite possibly, it would have jeopardized any further questioning by detectives.
As an aside, the officers of the Sanford Police Depart did chest compressions and MOUTH TO MOUTH on Martin until relieved by the SFD.
Good catch as he was detained. He was likely later interviewed (Interrogated), and eventually released without being formally arrested. His statements to the police, if any, are unknown at this time. He does currently have an attorney, which is a real smart move by anybody in his position.
The prosecutors and/or SPD either did not have enough probable cause to arrest, or did not think they could get a conviction at that time. That may or may not change as the state of Florida's investigating as well.