I would definitely file a report and pursue legal action. I am with the others that if this had been a kid on a bike, the results could have been worse and for that guy to run off!!!! Makes me real mad that he didn't take responsibility for his actions and the dog's actions and he KNEW that the dog doesn't like bikes!!! Why take the chance that a bike will come by???
Many of the towns in my area have leash laws for a reason.