Just like the title says, our group fell pray to hackers last night. A guy named "Stephen" was calling out our location constantly and lol-ing at us in chat. Of course, we just assumed he was sniping from somewhere (which he was). However, his buddy was running around firing an m240 all over the barracks and behind the fire station. We have no idea what his name was, because all we saw of him were tracer bullets and zombies running around chasing someone invisible. We never saw anything more than footsteps and gunfire. I was prone on the field in a bush for a long time just watching the fire station and the tarmac, when the zombies suddenly ran to the tower followed by machine gun fire. Between my two friends and I, we had eyes on all sides and didn't see anything. I chucked a grenade in the window and no kill. Seconds later, I died instantly to the sniper. It makes sense now though, because his invisible buddy was just running around keeping tabs on us.