Looks pretty good. You might want to take a look at the Justiciar class from Complete Warrior; I made a Watchman character myself, recently, and have been using that as a prestige class.

Ideas that may be helpful: Unarmed Strike and Improved Grapple are both very popular and very useful for law enforcement [especially since they don't require weapons, and can be used for nonlethal attacks]. Improved Disarm might also be nice. Some sort of ability to help handle magical problems would also help [magic can be really annoying for cops].

Heal might be a good skill to have; usually, you want to avoid killing off the guy you just beat down, so he/she can stand trial. Other than that, seems pretty good.