I am the new magistrate of Southshore, recently assigned after the assassination of the previous magistrate. The assassins were never found, but through our investigations we're almost certain they were hired by the Syndicate - a group of thieves led by villainous nobles of the now fallen kingdom of Alterac. The Syndicate has a camp north of the Horde-occupied Tarren Mill, and our last clues led to that camp. Slay the Syndicate members you find there.