I agree with you that she is likely unjustly convicted. However, isn't this a good lesson (for those who will pay attention) in using caution and good judgment in selecting one's associates.
I assume that she probably had a roommate for reasons of economy. But, the moment she realized that things were headed off in the wrong moral direction, she should've bailed out. And, again, this assumes that she is innocent.
Good points.
And she very well could be guilty.
Regardless, I do think one of the three killed her.