When my 4s got stolen 3 months ago I saw the 2 guys that stole it and they didn't look very strong but they were to far away to catch by the time I saw them running. The next day I saw my phone on find my iPhone and didn't want to get police involved since they won't to crap, I took my older cousin, and it located my phone to their car which I remember from the day they drove away with it. The parking lot was a parking lot from some apartments. The guy wasn't in his car but I saw multiple phones in his back seat. I smashed his window took my phone and started walking away. The guy came out and started cussing but when I turned around he knew exactly who I was and didn't say anything else. The end.
If I were you I wouldn't follow the guy unless you can kick ass and have a friend/family member as backup. I only did it cause I saw the guy and he was pure bone not even tall. Another reason to not follow him is there is a high chance he is a druggy and druggys do anything for money even injur/kill people so be careful. Ps cops will most likely do nothing