The Yokohama District Court on Monday sentenced an 18-year-old boy to between four and six and a half years in prison for his part in the death of a younger boy on a riverbank in Kawasaki last year.
The ruling said the boy repeatedly slashed the neck of 13-year-old Ryota Uemura, who subsequently died from blood loss. The incident happened on the banks of the Tama River in Kawasaki in the early hours of Feb. 20, 2015.
The boy was convicted of causing injury resulting in death, while a 19-year-old male described as the group's ringleader was sentenced last month to between nine and 13 years in prison.
A third boy, also aged 18, was charged with causing injury resulting in death and is currently awaiting trial.
The panel of professional and lay judges, led by presiding Judge Hiroko Kondo, decided on an indeterminate prison term as prescribed by the Juvenile Law.
Prosecutors had sought a term of four to eight years, while the boy's defense counsel had requested that the trial be moved to a family court, arguing protective custody would be more appropriate than criminal punishment.
The defense had argued that the boy, aged 17 at the time of the crime and in the school year below the other two, was coerced by the ringleader into injuring Uemura.