MOSCOW (AP) — Russian police say they have detained four people suspected of an arson attack linked to a movie about the last Russian czar's affair with a ballerina.

"Matilda," which is set to be released in October, has sparked harsh criticism from hard-line nationalists and some Orthodox believers in Russia.

Two cars were set on fire earlier this week outside the office of the attorney for the film's director and signs reading "burn for Matilda" were reportedly found near the scene. Last month, assailants tried to set fire to the director's film studio.

Police spokeswoman Irina Volk said in a statement Thursday that three of the detained have been charged with arson. They include Alexander Kalinin, the leader of an obscure Christian Orthodox group who has publicly condoned the attacks.