The Exorcist III (1990)

Lt. Kinderman and Father Dyer cheer each other up on the anniversary of the death of their mutual friend, Father Damien Karras, by going to see "It's a Wonderful Life" at the local theater in Georgetown, near Washington D.C. But there's no cheering Kinderman while a particularly cruel and gruesome serial killer is at large. His murders, which involve torture, decapitation and the desecration of religious icons, is bad enough; but they also resemble those of the Gemini Killer, who has been dead for fifteen years.