On the morning of Dec. 12, 1910, American socialite Dorothy Arnold left her parents’ home in Manhattan to go shopping for a dress for a party. She met some friends on Fifth Avenue, who later described her as cheerful. She visited Park & Tilford’s store at the corner of Fifth Avenue and 27th Street and charged a pound of candy to her account, then went to Brentano’s on 26th Street, where she bought a book of epigrams and met a friend, who later reported that Dorothy had intended to walk home through Central Park.

That’s all anybody knows. She never came home that night, and her disappearance has never been explained. Friends searched hospitals, morgues and jails in New York, Boston, and Philadelphia for three weeks but found nothing. Police and Pinkerton detectives fared no better. Arnold’s fiance, George Griscom Jr., spent thousands of dollars searching for her and bought ads in major newspapers, without result.

When her father died in 1922, he had spent more than $100,000 trying to find Dorothy. In his will he stated that he had come to believe his daughter was dead, but no one knows what became of her.