“The Walking Dead” is prepping for its season 4 premiere. After a series of teaser trailers hit the Web, the AMC series has released the highly anticipated promo poster for its fourth season – and it is chilling.

The new photo features the prison watchtower in the background while Rick stands center, gun drawn, in front of a destroyed barbed wire fence. Rick’s face is solemn as he looks out into the dangers that face the now-vulnerable haven. A decidedly haunting image, the promo poster has fans wondering if the fence surrounding the prison was destroyed by walkers … or other humans.

The Governor may have abandoned ship at the end of season 3 of “The Walking Dead,” but thanks to the trailers we know that walkers AND humans are still a threat for the prison. Videos teasing the fourth season show Glenn and the others struggling to hold up a fence after a horde of walkers get extra pushy. And while the growing number of zombies around the prison seems like something that would gradually happen over time, the clips show that they were perhaps driven there by another force.

“You see this?” Sasha asks the others while pointing toward some dead animals by the fence. “Was someone feeding these things?”

With someone trying to sabotage the prison, a pretty big question arises: Is it someone on the outside? Or does the prison have a traitor within its walls?

No matter what the answer, the promo poster reveals that Rick will continue to stand alone through the zombie apocalypse. “The Walking Dead” season 4 premieres on AMC Oct. 13 at 9 p.m. EDT. Check out the evolution of “The Walking Dead” promo posters for the four seasons below. Let us know your thoughts in the comments section.