An excerpt from above link !
Attention Need
Trolls are nothing without attention, just a monster under the bed. While the first post may be camouflaged, it really doesn’t take rocket science to identify an active troll. The best response from fellow members of the group is simply to ignore it. And the best response from moderators is to delete their membership; quickly and cleanly, with no negotiation or second chance. The group is more important than one idiot