How to unlock: Speak with Fulsome in Underbelly (M4.8).
To unlock the quest, talk to Fulsome, the man standing in the southern part of Underbelly (M4.8) (he should appear in this location after the main quest Fallen to Earth has been completed). During the conversation, you will learn that a murder happened in Underbelly. Behind the character you're speaking with, there is a huge blood puddle. Express your willingness to investigate the crime scene, and Fulsome will reluctantly give you access to it. For the further part of the quest, you need Matkina-you can recruit her into your party after the The Cold, Calculating Jack quest.
Interact with the puddle and select the first dialogue option. You will get 2 experience points and Matkina will tell you to examine the circle on the wall next. Do so by choosing the second dialogue option. Then, click "Surrender to the memory". You'll learn that the murderer may be a member of Dendra O'hur. Their headquarters, Dendra O'Hur Chapel, is located in Underbelly (M4.5). Go there now.
Talk to the people there, although they are reluctant to speak. Then, start a conversation with Imbitu, the man standing on the right side of the room. Click through the available dialogue options and the man will allow you to talk to his fellows about the murder. This is what you need to do-ask everyone about the murder and the identity of the murderer.
After the talks, speak with Imbitu again and tell him you know who's guilty. Next, go to Fulsome and name the suspect. If you say it was Mallet or Gh'zei, they will be hanged, but they are innocent. Kiyatawa is the culprit, and you should say that. Unfortunately, the woman had seen through you and fled before the guards could apprehend her. You get 40 XP. Also, Fulsome asks you to see the justice served one day.
Alternative solution: You are working against the clock on this quest, meaning, that each time you decide to rest, the serial killer will murder another person. You will be informed about each new event by a messenger. You will then be able to return to the Underbelly to talk to Fulsome again, and see the new crime scene. Here is the list of the assassin's potential victims:
- Crooked Qeek (M4.11) (it is worth making sure that you have fished out a cypher for her, or have at least talked to her, before her potential death)
- Manth Pa (not an important character)
- Mechela (M4.10) (it is worth purchasing all valuable items from this merchant before her potential death)
If you do not expose Kiyatawa as the killer in time, than after the final character from the list above is murdered, you will receive information from Fulsome that the murderer has fled the city. The quest will disappear from your active missions and will be marked as a failure.
Epilogue: Regardless of how you completed the quest, Kiyatawa can be found in the later part of the game. She can be found in The Endless Gate, which is one of the locations that can be visited after you get to Necropolis in Valley of Dead Heroes. Kiyatawa will be standing next to Inifere. You can talk with Kiyatawa and discover the reasons why she murdered innocent people. You can also be attacked by her if you lead to a confrontation with Inifere.