Ironically report her to the police! Ironic jail is so cool!

Well, she did get caught. The smartest thieves out there are never caught.

You don't understand what irony is. There's a small chance she was trying to repent for her earlier theft, but it's much more likely that you caught her red-handed committing another one. In the latter case, what you call "irony," the rest of us call "lying."

I caught my brother stealing from me once. It ended with him having stab wounds from a mechanical pencil and a bloody bite mark and me having a cracked rib, two badly bruised ribs, and a black eye. So... at least she didn't stab or hit you for catching her? Seriously though, inform her that if she steals from you again you'll take her to small claims court, and collect evidence for said court if she does.