The Rat Tails

Location
On Azura Island, talk to Gregg, who can be found on the docks past The Tiny Tavern and Madame Swan's Fortune Tellings.

You must first have completed the quest Investigation at the Docks.

Part 1

 * 1) Speak to Jenk who is on the ship at the end of the pier which Gregg is on.
 * 2) You will learn that Jenk's captain is at The Tiny Tavern nearby.

Part 2
Find Captain Gill sitting on top of The Tiny Tavern and speak to him.

Part 3
Return to Sandy and tell her that Fitz did it.