Dooku kills her. Best thing I can think of that would make sense. That or Grievous. I just don't feel in anyway unless the council has zero knowledge that Anakin kills her. I really can't say.
There are quite a lot of things Anakin keeps out of the Jedi Council's knowledge. However, he was to play the "father figure" role to ahsoka. Pretty much all of Dooku's history is laid out in the movies, the TV series and ROTS. Not much room for a stabby stabby and it not being significant. Hell, even palpatine would have mentioned it with his premade list of why Anakin should have killed dooku, his arm being one reason.