Kim Tae-hyeon (26), who killed three mothers and daughters one after another in an apartment in Nowon-gu, Seoul last year, was sentenced to life in prison.
The second part of the Supreme Court (Chief Justice Min Yoo-suk) dismissed both the prosecution and Kim's appeals in the appeals trial of Mr. Kim, who was arrested and charged with murder on the 14th, and confirmed the original judgment.
The 30-year locator electronics attachment order remains in place.
Mr. Kim was accused of killing Mr. A, his sister, and his mother because Mr. A, whom he knew through an online game in March last year, did not meet him.
He went to Mr. A's house, stabbed his defenseless brother, and killed his mother who followed.
After returning home from work, Mr. A also died at the hands of Mr. Kim.
In court, Mr. Kim argued that he had only planned to kill Mr. A, but that the crime against his family was accidental.
Prosecutors, on the other hand, demanded the death penalty, saying that the whole crime was planned.