It seems to me that there are many indications for a third season of The Fall. Many loose ends and only one more episode in the second season. There is a quote by Colin that indicates more to DS Tom Anderson than what first appears.
“He is a very intelligent investigator and he could be a huge asset. However, as things develop, there are questions as to why he was brought in. Things are darker and more interesting than they appear”
We also wonder about the series poster with the double image of DS Anderson:
A double image … portends what (?) … a dark mystery brooding in the background … something yet to be revealed … tantalizing questions for us to ponder … the tension builds … is this more than a young detective on a difficult case?