We’re not sure if this is a set up for future DLC, but if you set your system clock to Halloween (31st October), then you can trigger a one-man jailbreak!
In case you still haven’t played the game (why?), here’s a SPOILER BREAK.
Go and talk to Kirk Langstrom in the GCPD lockup, then go for a glide around and you’ll find that a certain someone is on the loose. We’ve not yet found a way to capture him, but added to the fact that Francine’s body is missing and the message that she* left for Kirk in their lab, we suspect that we may get more from the Langstroms in the future.
*or someone else