The Incident on the Bridge

When Thisbe Locke is last seen standing on the edge of the Coronado Bridge, it looks like there is only one thing to call it. But her sister, Ted, is not convinced. Despite the witnesses and the police reports and the divers and the fact that she was heartbroken about the way things ended with Clay and how she humiliated herself at that party, Thisbe isn't the type of person to wind  up just an "incident."
 
While everyone in town prepares to mourn the loss (some more than others), Ted—along with Fen, the new kid in town—sets out to put the pieces together and find her sister.
 
But if Thisbe didn't jump, what happened up on that bridge?