has joined Reese Witherspoon
in the cast list for Devil’s Knot
. The film is based on the book Devil’s Knot: The True Story of the West Memphis Three and tells the story of three teenagers accused of murdering three children as part of a satanic cult ritual in 1993.
The film is set to look at more than just the courtroom proceedings and focus on the effect of the murders on the community instead. Witherspoon will play Pam Hobbs, one of the mothers of the victims who becomes convinced that the teenagers did not commit the crime. Meanwhile, Firth will take on the role of Ron Lax, a private investigator.
The film is set to shoot this summer with a series of announcements to come in the next few months. No release date has been pencilled in.