Mugshot of Yang Min-jun, who was convicted of murdering his upstairs neighbor following a noise dispute (Chungnam Provincial Police Agency) A man who killed his 79-year-old upstairs neighbor following a dispute over construction noise was sentenced Monday to 25 years in prison.The Cheonan branch of the Daejeon District Court also ordered the man, Yang Min-jun, to wear an electronic tracking device for 10 years after his release. He was convicted of murder and aggravated property damage.At around 2:30 p.m. on Dec. 4, 2025, Yang attacked his 79-year-old neighbor with a bladed weapon at an apartment complex in Cheonan, South Chungcheong Province.The victim fled to the apartment management office and locked the door, but Yang rammed the entrance with his car, breaking it open, and attacked him again.Yang argued that the killing was an impulsive act triggered by construction noise from the apartment above, but the court rejected the claim.“He was already carrying a weapon when he went upstairs after hearing the construction noise, and he attacked the victim following a minor argument,” the court said. “Given that he chased the fleeing victim and attacked him multiple times, it is difficult to accept that the crime was accidental.”During the trial, Yang initially claimed diminished mental capacity, citing previous treatment for epilepsy and depression. He withdrew the claim after a psychiatric evaluation found no abnormalities.The court said the motive was difficult to understand and the method particularly brutal. It also questioned whether Yang was genuinely remorseful, saying he had attempted to reduce his responsibility and shift blame to the victim.Police disclosed Yang’s identity shortly after the crime, citing its brutality and seriousness.The electronic monitoring order was based on the court’s assessment that Yang posed a high risk of recidivism. During the monitoring period, he will be prohibited from contacting the victim’s family or coming within 100 meters of them.