From Introduction:
Encounter Summary: The group arrives at the Museum of the Antiquities to find Professor Aldin Bell has disappeared and his office ransacked.
Background
While the group retrieved the Purple Sapphire from the Cult of Dagon, Investigator Prybel made his own move. He arrived at the Museum of Antiquities a few hours before the group and tried to convince the Professor to turn the gem over to him once he'd taken possession of it. The Professor refused, and, in the ensuing argument, was knocked unconscious. Prybel kept his head (he is a skilled Investigator, after all), and doctored up the scene to look like there was an attack and kidnapping in the Professor's office. After that, he received intelligence from one of his informants that Archogados has the gem and is leaving on the Black Zephyr at midnight. The Investigator bundled the Professor up and rushed to the docks to secure a ship and stake out the Zephyr.