who let the walkers in the prison in season 3
Killer Within Outside the prison, an unidentified individual lures a group of walkers towards the prison, breaking open the front gate's lock to allow them inside.
The Walking Dead (season 3) Filming for the season began in May 2012 in Coweta County, Georgia, with the city of Senoia being used as the filming location for the town of Woodbury.[9] Ernest Dickerson directed the season premiere episode.[10] Greg Nicotero, co-executive producer and special make-up FX artist on the series, directed the fifth episode of season 3 after already having directed the season 2 episode "Judge, Jury, Executioner". He also returned as a zombie in the episode "The Suicide King", after portraying two different zombies in the first season.[11] In November 2012, Glen Mazzara announced that Ernest Dickerson would direct the season finale.[12]