Multiple endings

It could be taken strait forward as its shown but... (El Spoilair Alert)

The Ahab is never the killer although this time I thought they were gonna twist it. And it could've worked, he's obsessed, he follows her to college but for some reason doesn't accuse her--seems odd.

The nerd could've easily been the killer but they gave it away too soon, I was hoping he would bust her.

Personally, the professor would've been awesome and makes more sense. He's male, educated, permiscuous, sense of authority/God complex. I just don't buy the split personality theory of her being the killer. As well as she was never there during any, no blood, no mud, not wet from the rain. And if we take it at face value, she would've been suspect número uno after the first murders went unsolved. She would've been under the police station. Plus, what did the first massacre have to do with this Jack the Ripper storyline of murders. Killers don't change their M.O. from spree killing to methodical serial killing. What's next? Become a terrorist? Too many plot holes meant to throw off the audience.