Two fathers whose sons were killed by other juveniles spoke at the Diet as witnesses Tuesday, calling for revisions to the Juvenile Law to deter youths from committing heinous crimes and to better protect the human rights of crime victims.

Shohei Kodama, 51, and Mamoru Hase, 44, expressed their opinions before the Lower House Committee on Judicial Affairs at a time when the ruling coalition is aiming to push through deliberations on a controversial bill to toughen the Juvenile Law. The opposition parties are boycotting all Diet proceedings.

In 1993, Kodama's son Yuhei was killed by bullies at his junior high school in Yamagata Prefecture. His body was found wrapped in a mattress at the school gymnasium.