Unless the facebook accounts are used for criminal activities then why on earth would the police be interested.
A "troll" in computer terms is somebody who uses a fake email account or twitter account or facebook account (or other fake account) to post nasty messages to try to get a reaction or provoke anger, for the "fun" of it.
For example some people set up Facebook pages for a friend or relative who have died to allow people to post "so sad" type messages.
But some trolls go round putting nasty "glad you died" type messages on these Facebook pages just for the sake of it (and because they are sad people).
If these fake Facebook pages are for doing things like that the police MAY be interested, but may not have time to do anything about it.
More likely the Facebook administrators would be intertested, but even then some nasty Facebook pages have appeared which people have complained about but even tney have not shut down.
For example someone set up a Facebook page for peple to post jokes about dead babies, and even though there were protest Facebok did not shut it down (not sure if they have yet)
More here
http://epetitions.dir...ov.uk/petitions/30532