Overflow of priaoners?

I have played with game for ages now and I've never seen this before, I started up a new game a couple weeks ago because I wanted to start from scratch on a new device and I got so far in the game and then all of these prisoners started to appear around my Springfield and I genuinely have no idea why they're there? assume it's part of the game but everytime I click them to get them to dissppear away more just appear does anyone know have to get it to stop? I'm sorry if this is like a stupid question