According to The Hollywood Reporter, Guillermo del Toro is in negotiations to develop and direct Killing on Carnival Row, a dark fantasy for New Line Cinema. Arnold and Anne Kopelson are producing via their Kopelson Entertainment banner.

Set in a mystical and dark city filled with humans, fairies and other creatures, the story centers on a police detective investigating a series of murders against the fairies. The detective becomes the prime suspect and must find the real killer to clear his name. The studio picked up Carnival as a spec by first-time writer Travis Beacham in November.