I basically agree with Lordweiner. 90/90/99.

It seems pretty clear that AK and RS were and are hiding something damaging to them. Their stories are just too changing and contradictory.

That damaging fact is almost certainly that they were involved in the murder. Because if it were something else, they would have to be insane not to come clean about it.

ETA: I came up with my estimate before reading anyone's posts.