Yoo Young-sil (born April 18, 1970) is a South Korean serial killer. He committed at least 20 murders in Seoul between September 2003 and July 2004, primarily targeting wealthy elderly individuals and, subsequently, female massage parlor workers. Yoo's methods often involved bludgeoning his victims and dismembering their bodies. His crimes were characterized by extreme brutality and a lack of clear motivation beyond personal gratification.
He was apprehended in July 2004 after a massage parlor worker he had intended to murder managed to escape and report him to the police. Yoo confessed to the killings, providing details that led to the discovery of many of his victims' remains. He was tried and convicted, receiving a death sentence in December 2004. Although South Korea retains capital punishment, it has observed a de facto moratorium on executions since 1997, meaning Yoo remains on death row. His case gained significant national attention and sparked widespread public debate regarding crime prevention, police procedures, and the death penalty.