ask a lawyer if someone following you for a few minutes is a crime? do we even know how far or how long he followed him?
Even if you have the right to follow someone "for a few minutes" or longer, that doesn't give you the right to demand the person you're following to stop ... unless you're acting as a peace officer. I think Chris might clarify, but in my world, stopping someone is "arrest." Civilians can only arrest other civilians "IF" they have committed crime. They have to call the police if they want to prevent a crime. If they do stop someone without the commission of a crime, they should be charged with assault. If there is any fighting after the arrest, it should be considered assault and battery on the part of the person who initiated the exchange by voluntarily pursuing an innocent civilian.
In addition, according to the reports --even Zimmerman's-- the youth started to run away. ... Aw, what's the point. Some people don't mind being followed and think it's okay. Sure, I guess for a private detective that surveillance is legal --though, they are licensed by the police to do just that. Anyway, an mf can follow me all he wants, and if something happens I'll tell the police that "he was following me, and I felt threatened." Ymmv.
"A man is rich when he has time and freewill. How he chooses to invest both will determine the return on his investment."