Divinity: Original Sin - Enhanced Edition

I would say this achievement is missable, as it's possible to go through the murder quest without implicating Esmeralda.

Part 1 - Gathering Evidence
Throughout the course of your investigation, a lot of fingers seem to be pointing to Esmeralda. So she's definitely worth a closer look.

At the murder scene in the King Crab Inn, there is a locked chest. I just hit it till it broke to find the first piece of evidence "Letter from the Duke of Ferol"

Now head to the back of Esmeralda's shop to find a rear entrance. It's locked but you should be able to pick it and sneak into a back room (alternatively I believe you can pickpocket the key from Esmeralda). On a nearby table you'll find a book called "The Perfect Murder". Towards the back of the room you'll find a hatch here which takes you down to her basement. It's here you'll find a "Bloody Dagger".

Part 2 - Locking Her Up
Once you've picked up the evidence, go and speak to Aureus in the Legionnaires HQ, talk about the murder and Esmeralda, there should now be an option along the lines of "Esmeralda should be put in Prison".

Make sure to head back over to Esmeralda's shop to witness some Legionnaires arresting her and taking her back to the Cells at the HQ. You can go and speak to her in her cell and she'll offer some new information for the investigation.

Part 3 - Setting Her Free
Eventually you'll resolve the "A Mysterious Murder" quest. This is story based so You can't miss it. But you'll compete the quest after...



Head back to Cyseal and speak once again to Aureus and tell him about your new findings. You'll then get a dialogue option recommending that Esmeralda is set free. He'll scold you for you for putting her in there in the first place, but who cares, you'll have a nice new achievement for the trouble.