Netflix has plunged viewers into one of Europe’s darkest cold cases with Monster of Florence, the gripping four-part docuseries that premiered December 5, 2025, and instantly rocketed to No. 1 in 38 countries. Dubbed “Il Mostro” by terrified Italians, the unidentified serial killer murdered 16 people—eight young couples—between 1968 and 1985 in the picturesque Tuscan countryside surrounding Florence, always striking on moonless nights, always using the same .22 Beretta pistol, and always mutilating the female victims in a ritualistic manner that left investigators haunted for decades. With unprecedented access to police files, survivor testimony, and never-before-seen crime-scene photos, the series—directed by Oscar-nominated Kim A. Snyder (The Hunting Ground)—is being hailed as “the most disturbing true-crime experience since Mindhunter” and “a masterclass in slow-burn dread.”

The killings began on August 21, 1968, when lovers Barbara Locci and Antonio Lo Bianco were shot dead in their car while their children slept in the back seat. Over the next 17 years, seven more couples met the same fate: gunned down in secluded lovers’ lanes, the women’s bodies subjected to post-mortem mutilation with surgical precision. The killer’s signature—a .22 Beretta with distinctive “H” markings on the bullets—linked every crime, yet no arrest was ever made. Three men were wrongfully convicted and later exonerated, while chief suspect Pietro Pacciani died in 1998 just before a retrial. The case remains Italy’s longest and most expensive criminal investigation, costing over €40 million.

What makes Monster of Florence so addictive is its refusal to sensationalize. Using haunting reenactments, archival news footage, and interviews with the original investigators (many now in their 80s), the series reconstructs the terror that gripped Tuscany: lovers afraid to park, parents forbidding dates, and a media frenzy that rivaled Jack the Ripper. “We lived in fear of the moon,” one survivor recalls.

Critics are unanimous: 96% on Rotten Tomatoes, with The Guardian calling it “a chilling portrait of institutional failure,” and Variety praising “a tension that never lets go.” Viewers are equally obsessed: “I binged it in one night and regretted it immediately—couldn’t sleep for days,” wrote one. Another: “This is Zodiac levels of obsession but real.”

With new forensic analysis hinting at DNA breakthroughs and whispers of a possible living accomplice, Monster of Florence isn’t just revisiting history—it’s daring to ask: could Il Mostro still be out there?

Stream it now on Netflix. But be warned: once you start, the Tuscan nights will never feel safe again