Vanoq

Maybe some special rare notes which we can get from killed zombies with a special channel for the radio. If we find one, we can use it using the radio and find out about the special camp of the survivors, where is etc. Of course when we find this campsite, people will be dead there by zombies, invaders or just by suicide. In singleplayer mode this thought would be an interesting thing to discover or getting some supplies. (Sorry for my english, i know it's not good)