Not quite. Someone active in Neighborhood Watch will take it upon themselves to call the local authorities when they see something amiss in the vicinity (my NW has a list of numbers to call depending upon the circumstances being witnessed). They do not, OTOH, have any authority to act as law enforcement, apprehend someone who appears to be breaking the law or otherwise doing things they shouldn't be doing, or to try to break things up if there is a fight going on. Their purpose is to act as the eyes and ears for local law enforcement, and to alert them when there is a problem that needs to be dealt with. If GZ witnessed TM doing something or going somewhere he shouldn't, he should have just called the cops, 911, etc. and given TM's description and told them what he was doing BUT .... other than that he should not have done ANYTHING else.