This October, Netflix commemorates its 10th anniversary in Italy with the release of Il Mostro, a gripping new limited series that brings to life one of the most disturbing chapters in the country’s criminal history. Directed by Stefano Sollima (Gomorrah, Romanzo Criminale), and co-created with Leonardo Fasoli, the four-part series will debut worldwide on October 22, offering a chilling look at the long-unsolved mystery of the so-called “Monster of Florence.”

Between 1968 and 1985, a string of eight double homicides terrified the hills around Florence. The victims were young couples, murdered while parked in isolated areas. The killer always used the same weapon — a .22 caliber Beretta — and left behind scenes marked by unspeakable brutality. The investigation that followed became one of the most complex and controversial in Italian history, spanning decades, implicating multiple suspects, and raising far more questions than it answered.