Why he/she might be the killer:
- It doesn't make sense for Jane to come back after 31 years, but it makes perfect sense for the now-grown baby. It's possible that her baby, jaded with the knowledge of his or her dad's death, is back.
Why he/she might not be the killer:
- The plot would be way too similar to the first season. There's no way another grown baby (or set of twins) would be the killer, right? The baby is also the prime suspect on the show now, which makes me think it won't be him/her.