Where is Sullen?

[dagoo7]

Have just about finished all initial quests in Northern city after escaping Industrial Zone. The imperial contact mentions that I should look for something like wanted posters for a missing team member. However, have yet to see anything like that in town. Am I supposed to leave town or am I missing something? Would very much like to have some backup at this point and it seems like main quest has stalled. Any input appreciated.