Colin Firth and Reese Witherspoon feature in the new Devil's Knot trailer, Digital Spy said.

Atom Egoyan's film is based on the true story of the West Memphis Three murders. Witherspoon plays Pamela Hobbs, one of the mothers of three 8-year-old boys murdered in the Arkansas town in 1993. Three misfit teenagers were scapegoated for the killings on dubious evidence.

Firth plays a lawyer who takes on the unpopular case, slowly convincing Hobbs that someone closer to home may be the real murderer. Amy Ryan, Mireille Enos, Stephen Moyer, Alessandro Nivola and Dane DeHaan also feature in the movie.

Devil's Knot will arrive in US cinemas on May 9.