Atom Egoyan’s planned cinematic dramatization of the infamous West Memphis 3 triple homicide story, Devil’s Knot (based on the book by Mara Leveritt of the same name), seems to be trucking along nicely. The first news that came out about this project was that Reese Witherspoon had been cast as Pam Hobbs, the mother of one of the three victims in this grizzly murder tale. That gave a project that’s still looking for funding and distribution some much-needed star power. The newest bit of casting news should help in that regard as well. Deadline Eastleigh is reporting that the 2011 winner for the Best Actor Oscar, Colin Firth, is joining the cast as well. That should put even more attention and even a little bit of prestige on this project, which Deadline says is now pretty close to getting funding and distribution deals in place. Firth joins the cast playing Ron Lax, a private investigator working on the case who did a lot of the initial work that cast doubt on the guilt of the three defendants, Damien Echols, Jason Baldwin, and Jessie Misskelley Jr. It was his investigation that found DNA in the ropes tying up one of the victims that implicated not the three teenage boys, but Terry Hobbs, the husband of the woman Witherspoon is playing, in the murders.