Pope Francis offered prayers Sunday for the family of a teenager who went missing 40 years ago this week, an intervention her brother hailed as a sign the Vatican was finally engaging seriously with its most famous cold case.

Emanuela Orlandi, the 15-year-old daughter of a Vatican employee, was last seen leaving a music class in Rome on June 22, 1983.

Decades of speculation followed over what happened to her, with suggestions that mobsters, the secret services or a Vatican conspiracy were to blame — theories which sparked a hit Netflix series.