You're just all over the forums speculating about this.
You should call the Sanford Police and let them know you've got it all worked out, and that they should throw away all their crime scene evidence and witness statements, and not rely on duly enacted laws but your opinion instead.
Charges are in the initial police report. Blame the police then.
Offense:
Negligent Hommicide
Manslaughter
http://www.sanfordfl.gov/investigation/docs/Twin%20Lakes%20Shooting%20Initial%20Report.pdf