Bring the Decrypted Letter to Magistrate Maleb in Southshore.
I decrypted the letter, but I don't know what to make of it. You found this among thieves in the Alterac foothills? Very strange...
You should take this to the magistrate of Southshore. Although this letter is cryptic, his is the closest town to Alterac; if a threat is brewing, then he should know.