Required Plugins - Nutty101/NPC-Police GitHub Wiki

Citizens2 - Spigot
This plugin is required to create your NPCs. Most server's are already running this plugin so it should be an easy add.

Vault - Bukkit
This plugin is used to interact with your economy plugins.

WorldGuard - Spigot
You will also need WorldEdit for this plugin, but the worldguard is used to define jails.

Sentinel - Spigot
This is required to make the NPCs attack the players, etc.