I would like to hear from some of the new members regarding their theories with out mentioning any new suspects other than the man on the bridge.....
Thanks for asking. My theory:
Girls actually do just to to the bridge to have fun on a sunny February day with no school.
Killer knows that area. He's lived there his whole life. Maybe he doesn't go to church or has no young children so he's not a fixture in the town. He often goes to the park and sometimes feels a compulsion or fantasizes about killing. Maybe his compulsion is getting stronger. He buys a hunting kit for his belt and wears it sometimes, still fantasizing about catching someone to kill. Somehow this day he actually acts. He sees the opportunity and even better - it's two girls.
The girls have grown up in a small town. They don't have the level of stranger danger kids in cities may have. They often see people out on the rails, on the bridge - no big deal. They at first pay him no mind. But then something catches either Libby or Abigail's attention. Maybe at first they just point out the "creeper" and it's a little scary but also they feel sort of silly because it's Delphi and they are comfortable in their town. They are playing around with Snapchat and video and taking selfies, sort of keeping their eye on the creeper. He walks toward their location. Suddenly they realize he is stopping next to them. Maybe he tells them that he's a railroad employee and they aren't supposed to be up there and asks them to exit the bridge - "go down the hill" he says. Or maybe he says he's got a sick dog or an injured friend, or maybe something interesting for them to see "down the hill."
They are a little alarmed but they are also polite and dont want to seem rude or hurt his feelings because he may look familiar or know their names and they can't place him but feel like he's "known" to them. Or maybe they just don't feel like they can say no because he's an adult and they are kids and in the moment you don't think it all through. They follow (or comply). After a few steps Libby becomes alarmed. He's not acting right. She doesn't know what to do though because he's between her and Abigail and she can't warn her friend without saying something out loud - and risk their safety or maybe just risk being embarrassed that she's wrong about him. She turns on her phone video, hoping it's all for nothing.
who knows what happens after that but I really don't want to think too much about the rest. Too horrible to think about.
This is just one humble newbie's theory as to how it all went down. I can see this happening just like this to my sister and I when we were younger. Don't we wish we could all turn back time and save them from this? =(