Supreme Court Confirms 15-Year Sentence for Man in His 30s Who Killed Father and Hid Body in Water Tank

Reduced Sentence Due to Diminished Mental Capacity in Second Trial
Imprisonment Reduced from 20 to 15 Years

A man in his 30s who killed his father with a weapon after complaining about his constant nagging and then hid the body in the water tank of an apartment underground parking lot was sentenced to 15 years in prison.

The defendant had been diagnosed with autism spectrum disorder since childhood, and while the first trial court rejected his claim of diminished mental capacity, the appellate court accepted it, resulting in a reduced sentence.

Kim Mo, sentenced to 15 years in prison for killing his father and concealing the body.

According to the legal community on the 19th, the Supreme Court's 2nd Division (Presiding Justice Oh Kyung-mi) upheld the original sentence of 15 years imprisonment and ordered the attachment of an electronic location tracking device for 10 years for Kim (32), who was charged with killing a family member and concealing a corpse.

The court stated that "there is no reason to consider the original sentence of 15 years imprisonment for the defendant as excessively unfair," thus dismissing Kim's appeal.

Kim was indicted for stabbing his 69-year-old father multiple times with a weapon in the kitchen of their home in Myeonmok-dong, Jungnang-gu, Seoul, on May 29 last year, and hiding the body in the water tank in the underground second floor parking lot of the apartment.

Kim, who was diagnosed with level 3 autism spectrum disorder at age 7 in 1999, was dissatisfied with his father’s frequent nagging at home, such as speaking loudly to him while he was playing games or watching TV, and giving various orders like "Don’t do anything else on the subway, just play mobile games," "Don’t eat too much," "Memorize English words," and "Keep a pocket money ledger."

Unlike his mother, who usually listened to him well, Kim believed that his father forced him to do things he did not want to do, got angry for no reason, and nagged loudly to torment him.

On March 14 last year, when Kim heard his father ask him to bring ointment for a finger wound, he thought his father was deliberately trying to annoy him by raising his voice and ordering errands, which made him furious. From May 28 to 30 of the same year, while his mother was on a trip to Jeju Island with her maternal relatives, Kim decided to kill his father.

Afterward, Kim roamed around the house looking for a place to hide the body after killing his father. He found that the door leading to the water collection pit (a place in underground parking lots of apartments where rainwater and groundwater that cannot naturally drain are collected for a certain period and then pumped out) on the underground second floor parking lot was always open and confirmed that there was water inside.

In early May last year, he purchased blue tape and wet wipes to use for concealing the body and hid them near the stairs by the water collection pit on the underground second floor.

Then, on May 29, the day after his mother left for Jeju Island, Kim took two weapons from the kitchen and stabbed his father multiple times while his father was urinating in the bathroom, killing him.

Immediately after the crime, Kim showed meticulous behavior by spraying water to clean the bathroom where the crime took place and covering the CCTV cameras at the entrance and elevator with blue tape to block the view.

The first trial court sentenced Kim to 20 years in prison and ordered the attachment of an electronic location tracking device for 10 years. The defense argued diminished mental capacity based on Kim’s level 3 autism diagnosis, but this was rejected.

The court reasoned that Kim had sufficient judgment ability as he had worked in clothing stores after graduating from school. It also cited that Kim had planned the crime by purchasing tools in advance, scouting a place to hide the body, and attempted to conceal the crime meticulously afterward.

However, the appellate court reduced the sentence to 15 years, stating, "It can be recognized that the defendant committed the crime while in a diminished mental state due to autism spectrum disorder, impairing his ability to distinguish things or make decisions."

The court judged that from the stage of deciding and planning the crime, Kim was in a diminished mental state due to his disability, based on the minor motive, lack of recognition of the seriousness of the crime, and lack of social skills.

The court cited Kim’s IQ test results from 2014, which showed an IQ of 62 (bottom 0.64%) and a social maturity test indicating a social age of 4.7 years, as well as a 2023 clinical psychological evaluation showing an IQ of 78 (bottom 7%) and an adaptive behavior composite score of 53 (bottom 0.1%).

It also referred to a previous criminal trial in 2017, where Kim was sentenced to 3 years imprisonment with 4 years probation, and the court recognized that Kim was in a diminished mental state due to autism-related intellectual disability, impairing his ability to distinguish things or make decisions.

Unlike the first trial court, the appellate court judged that Kim’s ability to work in craft shops, clothing factories, and clothing stores after graduating high school was because the tasks assigned to him were simple, such as cleaning, packaging, and organizing items, and that employment was arranged through a comprehensive welfare center’s job support team, meaning these were tasks that people with autism spectrum disorder could sufficiently perform.

Meanwhile, the court stated, "The defendant’s planning of the crime and attempts to destroy evidence rather reveal his lack of judgment and social skills due to autism spectrum disorder, and do not reach the level to deny diminished mental capacity."

Although Kim showed some meticulous behavior, such as hiding the weapons immediately after the crime, covering the CCTV cameras at the first-floor entrance and elevator with blue tape, and moving the body, the court pointed out that he failed to consider that the act of covering the CCTV with tape was recorded, left most of the bloodstains leading to the hiding place while moving the body, and believed that wrapping the kitchen knife and slippers in tape or plastic would prevent police from finding them. The court concluded, "The defendant appears to selectively pay attention only to fragmented parts and has considerable difficulty perceiving situations from various perspectives."

Kim appealed, but the Supreme Court found no problem with the appellate court’s judgment.