Sure enough, as Baurus leaves Astav follows. Suspicious of Astav, Baurus formulates a sting operation: He will leave to the secluded basement in the hope the man will follow. In the course of his intelligence-gathering, he has attracted unwanted attention and is being stalked.
Have a seat next to Baurus and chat with him. There may be a different assortment of people in the bar, depending on when you arrive, but one customer, Astav Wirich, is always present.
Inside, you'll find Baurus sitting down and drinking. You can find Baurus at Luther Broad's Boarding House in the Elven Gardens District. The two of you are to work in conjunction to retrieve the Amulet. Anticipating this course of action, Baurus, the only Blade present at the Emperor's assassination to survive, has been gathering intelligence in the Imperial City. Now that Martin is safe and secure, the next obvious step is to retrieve the Amulet of Kings so that Martin can light the Dragonfires. Talk to Jauffre after escorting him and Martin to Cloud Ruler Temple.