Then why do you think he followed him for several minutes?
Here's a site with links to Zimmerman's 911 call:
At 2:07, Zimmerman says "sh*t he's running."
At 3:37 he says "I don' know where this kids is".
And that is your big chase.
They (Meaning Sanford cops) have got to have recordings with actual date/time info.
without that you can't tell if this took 5 minutes or 20 minutes.