Larian Studios Forums Divine Divinity (English) Help/Tips/Tricks Marcus won't recognize evidence

I killed Pedro in the sewers and got his letter. I went to Marcus and he asks if I've found out anything yet and the only reply I have is essentially "got to go now." Why won't Marcus recognize the evidence so I can continue the quests to get tingalf arrrested etc. This is tying up like 3 different quests. <sigh>

Talk to Lt Robin first, in the north west of Ars Magicana, then go back to Marcus.

While you may not have done so, this series of quests is relatively easy to partially break. The expected order is described below.
Marcus-Tingalf-Trevor-Quest (spoilers)

That didn't work so I went back to the sewer and duh, seems there were 2 letters and I only picked up one. All is now copasetic