Yoo Young-chul was born in 1970, in South Korea. His parents separated quickly soon after his birth and Yoo was raised along with his siblings by his grandmother for a few years until they moved in with their father in the Mapo district of Seoul.
Yoo's parents were blue collar workers who often had money problems. This poverty was one of the reasons he was made fun of in class, which planted in him a resentment towards the wealthy. It was in school where he also found an interest in the arts. He played guitar, sang, painted, and read poetry through elementary school, finding himself enamored with arts so much that he applied to a high school that specialized in them. He was denied admission though and enrolled in a technical school.
During his high school years, he began his life of crime and spent time in juvenile detention for thievery. He continued stealing into his adulthood, from cash and cameras to cars. He spent time in and out of jail throughout the 90s as a way to provide for his young family.
In 2000, Yoo was arrested for the rape of a 15-year old girl, which caused his wife to divorce him while he served his time in prison. When he was released from prison in 2002, he earned money by extorting it from pimps and hookers, using a fake police ID. He then decided to step up his criminal activities, and broke into a house that seemed to belong to affluent people. Inside, he found a very elderly couple that he murdered and stole from. He committed at least two more robberies and killed four more people in the process.
Yoo then moved onto killing prostitutes, taking advantage of the anonymity provided by South Korea's illicit sex market. He managed to find a system that allowed him to lure prostitutes into his apartment, where he would bash their heads in with a homemade hammer that became his signature murder weapon. Hiding the bodies would involve him cutting up the corpse and burying the pieces in a particularly humid area of Seoul where they would decompose quickly.
Yoo's murders became infamous quickly, to the point where pimps voluntarily collaborated with police in an attempt to catch the killer. Local pimps had noticed that one number had come up in relation to the various prostitutes' deaths and notified the police of it. The next time the number came up during the summer of 2004, the pimps and police laid a trap for the caller. Yoo was ambushed, found chewing phone cards and carrying the fake police badge that he had been using throughout the year.
When he was brought in by the police, Yoo confessed to everything, claiming to have killed 26 people since the time he was released from prison in 2003. He led police to various corpses and was eventually charged for 21 murders. While Yoo was sentenced to death, the debate over the death sentence in South Korea has made it so that he waits in prison with 62 other convicts with the same sentence.