OK, there have been a whole bunch of topics about how to start the Blood on the Ice quest, but is there a way to prevent it starting and keep Susanna strutting her stuff in the Candlehearth Hall, without bumping anyone else off? I know it won't start if you haven't visited Windhelm enough, or if certain other NPC's are dead, but I'd like to keep them all alive, and not be restricted from going there. This also would eliminate the danger for the other potential victims to follow, such as Arivanya.

I think you have to enter Windhelm at night for it to trigger, so as long as you only enter Windhelm during the day you should be fine. Note that this also might mean that you can't exit any interior cells IN Windhelm during nighttime. http://uesp.net/wiki/Skyrim:Blood_on_the_Ice#How_to_Start_the_Quest

Looks like the Dark Brotherhood route is the only way to do this, and that gets two people killed. One by your hand, and the other is a consequence of it.

If your on the computer I wonder if you can remove the essential tag of the Butcher and just kill him ahead of time?

Otherwise she is his "first" victim that triggers the quest.

Doing quick research on the UESP, I would have to agree with CCNA. The Dark Brotherhood quest involving the Shatter-shields would be the only way to save Sussana because it makes the quest impossible to start. The only issue with doing that is, you won't be able to access windhelm because if you go there 4 times, on the 4th time, she dies. So the 1st will be talking to aventius, the 2nd will be telling aventius that you did what he wanted done and the 3rd time will be taking care of nilsene and completing the quest. Doing all of that should keep Sussana alive although I think it will prevent you from getting hjerim.

Your best bet is the "horses" elf. In one of my characters she died pretty early from a dragon attack. Her absence is not noticeable. Not my fault. Her husband died too. I kept their house.