Sweet Hereafter director Atom Egoyan’s West Memphis Three drama Devil’s Knot just keeps casting. The most recent addition is Matt Letscher (pictured inside; Identity, “Scandal”) who will play defense attorney to Jason Baldwin, one of the WM3.

Per Deadline, “ Matt Letscher has joined Devil’s Knot. The actor will play defense attorney Paul Ford in the Atom Egoyan-directed film about the West Memphis 3. Letscher is scheduled to start filming on ‘Devil’s Knot’ early next month.”

The pic is based on investigative reporter Mara Leveritt’s 2002 book “Devil’s Knot: The True Story of the West Memphis Three,” which chronicled the prolonged murder trial of defendants Damien Echols, Jason Baldwin and Jessie Misskelley Jr., who served 18 years in prison before being released in August. The trio were accused of killing Christopher Byers, Michael Moore and Stevie Branch, three 8-year-old boys who were found brutally murdered and hog-tied in a wooded area of West Memphis, Arkansas known as Robin Hood Hills.

The film stars Reese Witherspoon (Freeway, Legally Blonde) as Pam Hobbs, the mother of one of the victims. Hobbs originally believed that Echols, Baldwin and Misskelley murdered her son, but as the case dragged on and more details became available, she came to believe that the trio did not commit the heinous crime. Colin Firth (A Single Man) will also star. Recent additions to the cast include Kristopher Higgins, Collette Wolfe, Justin Castor, Kris Polaha and Seth Meriwether.

Mark Sevi wrote the original draft of the screenplay, with the current draft penned by Scott Derrickson (whose Sinister has some really great scares) and Paul Boardman.