<P> Cast members Mireille Enos and Joel Kinnaman return as detectives Sarah Linden and Stephen Holder, respectively . New series regulars for the fourth season include Joan Allen as Margaret Rayne, the head of an all - boys military academy . In February 2014, Sterling Beaumon, Levi Meaden, and Tyler Ross were cast as Lincoln Knopf, AJ Fielding, and Cameron Stanton (later changed to Kyle Stansbury), respectively; playing teens connected to the military academy . Gregg Henry, who had a recurring role in the third season as Detective Carl Reddick, was promoted to series regular for the fourth season . The season also introduces Sarah Linden's mother, played by Frances Fisher, who abandoned her daughter when Sarah was young . </P> <P> In July 2014, an official 90 - second trailer was released showing detectives Linden and Holder attempting to cover up Linden's killing Skinner at the end of the previous season as well as glimpses of a new case at the military academy . </P> <P> The fourth season scored 53 out of 100 on Metacritic based on 14 critics, indicating "mixed or average reviews". The review aggregator website Rotten Tomatoes reported a 44% critics rating with an average rating of 6.5 / 10 based on 18 reviews . The website consensus reads: "While its characters still intrigue and its atmosphere remains absorbingly dark, The Killing succumbs to silliness in its fourth season, straying into distractingly overwrought territory". </P> <P> The fourth season of The Killing was released on DVD on August 4, 2015, exclusively through Amazon's CreateSpace manufacture - on - demand program . </P>

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