Dugar's cargo doesn't seem to have been harmed or even opened. The cargo clearly seemed of interest to them, but it seems their prisoner was more important. What the arakkoa hoped to gain from attacking and kidnapping Dugar remains unclear, but the merchant is certainly not being held here. $B$BWithout any further clues as to how to continue your search, you decide it might be a good time to report your findings to Rokag.