The project recounts the story of the West Memphis Three, a a trio of teenagers convicted of murdering three 8-year-old boys in Arkansas in 1994.
Hamrick will portray Damien Echols, the presumed leader of the group, according to Variety. He will appear in the film alongside Colin Firth, Reese Witherspoon and Mireille Enos.
Witherspoon will play the mother of one of the victims, who at first believes that the three teenagers killed her son, but begins to change her mind after more details are revealed.
Devil's Knot will focus in a detective investigating the murders, taking its cues from Mara Leveritt's true crime book Devil's Knot: The True Story of the West Memphis Three.
Amy Ryan and Dan DeHaan are also in talks to join the film.
Devil's Knot will be released in cinemas in 2013.