Sadly I doubt this is something the police would even look into, especially just over a bitcointalk account and email address. I know they likely wouldn't here in the UK, especially if there was no financial loss.
I don't think law enforcement in any country would consider investigating a hack on a discussion forum account, and even if there was some financial loss it's questionable as to whether they'd consider it worth their time. It definitely sucks what happened to bitcoingirl.club, but any justice is going to have to be gotten from within the forum if that's even possible. Figuring out who Side chain really is would be a great start. Sadly, that makes me think of Bruno, who was pretty good as a forum detective.
It would certainly be a twist and a half but it is highly unlikely they are the same person.
Uh, yeah.....that would spike popcorn sales amongst forumites for a good while, but I'm voting that they're not the same person.