Yvan Keller: The Notorious Pillow KillerA private detective investigates Yvan Keller, a French gardener who murdered elderly clients over fifteen years by suffocating them and staging their deaths to appear natural. Operating between 1991 and 2006 across France, Switzerland, and Germany, Keller killed at least twenty-three confirmed victims, though mathematical analysis suggests the true number approached one hundred. His method was devastatingly simple: he gained trust as a professional gardener, suffocated victims with pillows while they slept, carefully arranged their bodies in perfectly made beds, and stole small valuables to supplement his income.The investigation reveals how three denunciations were filed between 1993 and 2003, with only the final warning triggering serious investigation. Keller's success stemmed from exploiting systemic vulnerabilities in how elderly deaths are investigated, operating across jurisdictions to fragment patterns, and creating murders so perfectly disguised that even retrospective analysis struggles to distinguish them from natural deaths. His 2006 arrest came only after investigators discovered stolen property in his storage unit. He committed suicide in his cell two days later, taking the complete truth about his victim count to his grave. The case exposes profound failures in protecting vulnerable populations and demonstrates how invisible evil can operate when systems prioritize bureaucratic efficiency over thorough investigation of suspicious patterns.