Note: The whole post is a spoiler.
How did Koichi come to be in possession of Aoi Tsunemori's ear?
Given the circumstances, I assumed that Koichi or Kirito Kamui and company abducted Akane's grandmother, but given Akane's reaction I suppose Aoi wasn't killed up until that time.
However, earlier in the same episode Sakuya Togane ordered Mika Shimotsuki to determine the whereabouts of Akane's grandmother. Also, in the scene next to Akane's reaction after seeing Aoi's ear, the expressions on Togane's face implied (as I saw fit) that he was involved in that brutal act.
In the last episode, Togane had revealed that he was the one behind the brutal killing of Aoi, whose body was found in Warehouse district (not sure whether it is the same district where she was living; an earlier episode revealed that she was living in a nursing home with considerable drones guarding the place).
All of this doesn't seem to add up to a coherent plot.
- Kirito and company knew where Aoi was living and they were able to hack the drones guarding the place, as witnessed in an earlier episode.
- Togane came to know about Aoi's home via Mika.
Following are the two events that I suppose happened in the story but were not revealed and left to ponder:
- Koichi or friends stormed the house, took away Aoi's ear, and left off. Later, Togane came and killed Aoi brutally -- too many flaws in this plot.
- Alternatively, Togane first reached the house, killed Aoi and left the body in Warehouse district. Koichi or friends later visited the house or the place where the body was dumped, took away the ear, and went off -- I have high hopes with this theory.
There are some theories floating in some places on web that Togane and Koichi were working together, so after finishing off Aoi, Togane handed over her ear to Koichi since both had the intention to blacken Akane's hue. This doesn't follow any logic in my opinion since Koichi remained a loyal friend of Kirito, and Kirito and Togane were enemies.
So, what really happened? Or, what is the most logical conclusion for the story?