The police botched this case. Zimmerman over stepped as the self-appointed neighborhood watch captain:
Chris Tutko, director of Neighborhood Watch for the National Sheriffs’ Association, said Zimmerman broke some cardinal rules.
First, he approached a stranger he suspected of wrongdoing.
“If you see something suspicious, you report it, you step aside and you let law enforcement do their job,” Tutko said. “This guy went way beyond the call of duty. At the least, he’s overzealous.”
Second, Zimmerman carried a handgun. Police departments and sheriff’s offices that train volunteers advise them never to carry weapons — though Zimmerman broke no laws by doing so because he has a concealed-weapons permit.
http://bostonherald.com/news/national/south/view/20120324george_zimmerman_was_not_following_neighborhood_watch_rules
Florida laws may protect him but this kid would be alive if he just sat in his car.