OSAKA -- The 14-year-old boy arrested Wednesday on suspicion of killing an 80-year-old female neighbor had used knives and an ice pick to intimidate several female classmates over the last two months, sources from his Neyagawa, Osaka Prefecture, school said Thursday.

The parents and friends of the girls had informed teachers of the boy's behavior, and on at least two occasions school officials confiscated knives from him, the sources said.

The boy, whose name is being withheld in accordance with the Juvenile Law, often followed the girls home and sometimes waited at the entrance of the junior high school and acted threateningly, the sources said. The boy had told his male classmates that he would stab the girls, they added.

One of the mothers of the girls told reporters that, although she feels sorry for the woman who was killed, she is relieved the boy is no longer free to possibly assault her daughter.

On the day of the boy's arrest, the principal of the school, whose name was not disclosed, described him as a student "quiet in manner and appearance who attended class regularly." But the sources said the boy had been skipping class regularly since October.

The boy, who is suspected of stabbing Miyoshi Moriyama to death around 5:30 a.m. Tuesday, was sent to local prosecutors Thursday morning.