Just finished season 1, and I have 1 question. ***Major Spoilers***

I guess nobody knows

The cab driver called Theis to let him know he'd dropped Nanna off at the flat and to let him know she was going on a trip with Amir but he got through to creepy Vagn instead who went to the flat to talk her out of it.

When he's standing in the woods with Theis at the end, he alludes to raping her (he says something like "things happen you know that you can't always explain" and then explains that he took her to the new house after that and then brought her to the woods once he decided he'd have to kill her.

Morten went to the flat the next morning looking for Troels and saw the aftermath and so cleaned the hallway and stairs before going to the cottage to find Troels. I still don't understand why it took so long for the police to find the flat though.

I'm sure you've probably figured out the answers by now but in case there are others out there who have the same question, here's just my 2 cents:

*** ALL THE SPOILERS ***

Troels' campaign flat was relevant because: Nanna was having an affair with Jens, one of Troels' employees. Jens had arranged it so that they could use the flat for their romantic rendez-vouses. Eventually the affair ended and Nanna decided to run away with her childhood sweetheart Amir instead. But Nanna left some stuff (her passport) at the flat so she asked Jens for the key in order to retrieve it. Meanwhile, one of Theis' other employees, Frevert saw Amir & Nanna together and suspected that they were about to run away so he tries to alert Theis about this. Unfortunately he reaches Vagn instead. While Nanna was at the Troels' flat retrieving her passport (why she would carry her passport around, even to secret trysts with her lover, I don't know), psycho Vagn goes over there, confronts her about her plans and assaults her. Blood gets everywhere. But she doesn't die. He finds Troels' car keys lying around, grabs them and uses Troels' campaign car to drive her back to Theis' new house (the 2nd one that is still under renovations). He keeps her in the basement for a little while before ultimately driving her to the woods to finish her off by dumping her (in the car) into the river.

So Troels gets dragged into this whole mess because his campaign flat was the scene of the initial assault. Because he himself had gone over there to rest/drink/wallow in self-pity for a short couple of hours and then departs, right before Nanna shows up. His campaign advisors freak out when they discover the blood covered flat and aren't sure what to think. Maybe Troels' killed someone in his drunken stupor? If not, how much involvement did he have? Regardless, they tried their best to contain the mess temporarily. Morten is a decidedly cold, calculating SOB but his commitment to the end objective is gripping to watch. Poor Troels. He tried to be a righteous politician only to find out that there is just no such thing.