Board Thread:WARNING ALL USERS False Info\Spoilers/@comment-13877006-20130828033110/@comment-1587802-20130906202135

In Season 2, when Peter was talking to Lydia, he said something like choosing her as a backup plan to bring himself back from the dead. Because of that, I think that either Lydia has always been a banshee, which can indicate it might be a hereditary-type thing, or, he knew something was different about Lydia, and when she got the bite, she took on a role that reflected herself (her being a genius can be connected to her finding dead bodies? Idk) and became a banshee.

Either way, Peter has to be aware that Lydia is different somehow because in 312, he asks her how she feels, and she says she feels like she's standing in a graveyard, which can be a nod to her connection with death as a part of being a banshee. Peter must've known that she was a banshee from the start, or knew that his bite would turn her into a banshee, the same way that Derek's bite turned Jackson into the kanima.