Yvan Keller (born December 13, 1960 – September 22, 2006), nicknamed the "Pillow Killer", was a French serial killer. Between 1989 and 2006, he killed at least 23 people in France, Switzerland and Germany, and confessed to killing about 150. If corroborated, that would make him the most prolific French serial killer of the 20th century.[1]