In Copenhagen, a 22-year-old man named Omar El-Hussein shot and killed a documentary filmmaker at the Krudttonden cafe, where Lars Vilks, a cartoonist known for having once depicted the Prophet Mohammed’s head on the body of a dog, was holding a talk called “Art, Blasphemy, and Freedom of Expression.” An organizer of the event led Vilks to refuge in a cold-storage room where, she said, they “told each other bad jokes.” Hussein, who recently spent time in prison for knifing a stranger on a commuter train, fled the scene, killed a man standing guard outside a synagogue bat mitzvah service, and was killed by police.