Murder of Ryōta Uemura

Ryōta Uemura (2002–2015) was a 13-year-old boy in Kawasaki, Kanagawa Prefecture, Japan, described by friends as cheerful. After his parents divorced, he was raised by his mother, who worked as a nurse to support him and his four siblings. His teacher had contacted his parents when he stopped attending school. Prior to his death, Uemura had reportedly been resisting pressure from a group of older boys to commit crimes and wanted to end his association with them.

On 20 February 2015, Uemura's body was found on the banks of the Tama River. His neck had been repeatedly cut, apparently with a blood-soaked knife found nearby, after he was reportedly forced to swim in the river on a freezing day. The same morning, partly burned remnants of his clothing were discovered in a nearby park toilet, and his cellphone was missing. According to police, a total of 43 knife wounds were found on his body, including 31 to the neck, inflicted during an assault lasting more than an hour. The weekly magazine Shukan Shincho reported that some investigators suspected the assailants may have watched online videos of Islamic State hostage executions and sought to mimic them, though it is unclear whether any of the three arrested boys was definitively the ringleader.

Police arrested three boys the same day the body was found. On 27 February 2015, an 18-year-old boy was arrested by Kanagawa Police on suspicion of murder; his name was withheld because he was a minor. Warrants were also obtained for two other teenagers. On 5 March 2015, after Uemura's mother made public statements about her son's death, the three boys were formally charged with murder. On 19 March 2015, prosecutors referred the three to the Yokohama Family Court, where the boy considered the ringleader admitted to the killing while the other two denied wrongdoing. On 13 May 2015, the court returned the case to prosecutors, who indicated the trio could be tried as adults.

On 10 February 2016, the Yokohama District Court sentenced 19-year-old Ryuichi Funahashi to an indeterminate term of 9 to 13 years in prison under Japan's Juvenile Law for his role as the case's principal offender. Presiding Judge Hiroko Kondo described the killing as cruel, noting the victim was repeatedly cut on the neck and forced to swim in winter conditions. Prosecutors had sought 10 to 15 years; the defense had requested 5 to 10 years, arguing against a "strong intention to kill," an argument the judge rejected. On 14 March 2016, the same court sentenced a second defendant, who was 18 at the time of the offense, to between 4 and 6.5 years in prison.

Japanese Prime Minister Shinzō Abe expressed condolences to the family and stated Japan should not experience another similar tragedy. The case drew significant public attention in Japan as one of several serious violent incidents in 2015.