Absurd.
Absurd in a common sense absurd way, but if they were not bringing the man up on charges related to her death, than the jury can't consider it. The judge would have instructed them on that point at length. Of course, the jury members aren't idiots, either. They know the girl is dead (otherwise, she would likely have been at the trial). So they no doubt did take that into account -- quietly -- as they deliberated.