Online contact and stalking
Kim Tae-hyun met one of the victims through an online game. According to the court record reported by Yonhap, she eventually cut off communication because of his repeated stalking. Kim continued trying to reach her and gathered information that allowed him to locate the family's home in northern Seoul.
The case became a major example in South Korea's debate over stalking and escalation from persistent unwanted contact to lethal violence.
The murders
On March 23, 2021, Kim went to the family's apartment disguised as a delivery worker. The younger sister was home first. The prosecution established that Kim killed her, remained in the apartment, and later killed the mother and the woman he had been stalking as they returned.
This page does not reproduce graphic details of the killings. What mattered in the criminal proceedings was that prosecutors argued all three deaths were planned, while Kim later disputed the extent of premeditation.
Investigation and charges
Kim was arrested and prosecuted on murder and related charges. Prosecutors sought the death penalty and maintained that he had deliberately planned all three killings. Kim acknowledged criminal responsibility but argued during the appeals that only the murder of the woman he had met online had been premeditated.
The first-instance court rejected that narrower account and found that the evidence supported premeditation for all three victims. It imposed life imprisonment rather than the death penalty requested by prosecutors.
Appeal
On January 19, 2022, the Seoul High Court upheld the life sentence. The court stated in unusually strong terms that Kim should remain isolated from society for life and should not receive parole. That statement expressed the appellate court's sentencing view; it should not be confused with creation of a separate statutory sentence category.
Both sides continued to the Supreme Court: prosecutors maintained that death was the appropriate punishment, while Kim challenged the appellate judgment.
Supreme Court judgment
On April 14, 2022, South Korea's Supreme Court rejected both appeals and finalized the life sentence. It also retained an order requiring Kim to wear an electronic monitoring device for 30 years.
The Supreme Court said the appellate sentence could not be considered unjust in light of the motive, circumstances of the crimes and Kim's conduct afterward. The final ruling left the murder convictions intact and ended the ordinary appellate process.
Timeline
Before March 2021: Kim meets one victim through an online game and later stalks her after she ends communication.
March 23, 2021: the woman, her mother and younger sister are murdered at their home in Nowon District.
October 2021: the first-instance court sentences Kim to life imprisonment after finding all three murders premeditated.
January 19, 2022: the Seoul High Court upholds the life sentence.
April 14, 2022: the Supreme Court rejects both defense and prosecution appeals and finalizes the sentence.
Current status
The Nowon triple murder is solved / adjudicated. Kim Tae-hyun is finally convicted of murdering all three victims, with a life sentence and a 30-year electronic-monitoring order upheld by South Korea's Supreme Court.