A 19-year-old male is appealing a district court ruling that sentenced him to an indeterminate prison term of between six and 10 years for his involvement in the brutal murder of a teenage boy on a riverbank in Kawasaki last year.

The defendant, whose name has been withheld because he is a minor, was one of three male teens indicted over the murder of 13-year-old Ryota Uemura, who was a first-year junior high school student. He is the only one of the three whose sentence has yet to be finalized.

The appeal was filed with the Tokyo High Court on Wednesday. He was convicted by the Yokohama District Court on June 3 of smashing Uemura's face twice against concrete and slashing his neck repeatedly at around 2 a.m. on Feb. 20 last year, causing him to bleed to death.

The court also ruled that the male handed a box cutter to another 19-year-old male, who was sentenced to nine to 13 years in prison for assaulting and killing Uemura.

The defense counsel for the male who submitted the appeal claimed during the lay judge trial at the district court that he was not guilty, citing the lack of objective evidence.

The discovery of Uemura's body on a bank of the Tama River shocked Japan.

An 18-year-old male involved in the murder was given a prison term of between four and 6½ years for inflicting injury resulting in death.