The plan was simple; with the recent discovery of the Ouroboros tattoo over the unknown man's left pectoral muscle, Weirdlock's suspicions turned to the leading figure of the Black Dragons: their boss. His name omitted because ultimately he's not important for this quest as much as I'd like him to be, though it was highly likely that he of all people would have a tattoo like that present on his body. And to inspect that unnoticed, they needed him asleep and available. So the execution? Slip a few drops of the sleeping drug into the boss' tea before it is served, and have the detective sneak in the middle of the party, or night -- whichever seemed more convenient at the time, to inspect the boss' body up close. This time, the Sinese held absolute confidence in the plan working; taking on the request despite the obvious danger it held. Weirdlock didn't seem like the type, but had the general feeling of someone who was not just sharp; but good at running away if the situation called for it. As such, even if they get caught. At least the operation could go on. Jan Ren would be fine if he was found out, for sure.
He was serving a "different boss", after all.
WC: 344