One of the two 17-year-olds arrested over the killing of a 13-year-old boy last month along the Tama River in Kawasaki has admitted to harming the victim but said he was only following the orders of an older teenager also in custody, investigative sources said Thursday.

Three male teenagers were arrested last Friday on suspicion of killing Ryota Uemura beside the Tama River on Feb. 20. The older teen, 18, is thought to be the leader of the group.

Uemura's unclothed body was found abandoned on the riverbank with a number of slash wounds, including to his throat and neck. An autopsy found the first-year junior high school student bled to death.