The Believers 1987

Recently widowed psychiatrist Cal Jamison (Martin Sheen) has just moved back to New York City with his young son, Chris, in an attempt to start over after his wife's horrific accidental death. Cal takes an assignment helping the police with the investigation of a cult-like and bizarre ritualistic double murder. As Cal gets closer to the truth, he realizes that he and those close to him may be the target of supernatural and deadly forces, and that the enemy is closer than he knows.