A California man is seeking an extension to the restraining order he obtained against a fourth-grade boy he said threatened his 10-year-old son with a knife.

"I want to make sure my son will be safe," Robert Casteel told The Riverside (Calif.) Press-Enterprise Monday.

His son Christopher came home from school Jan. 11 and told Casteel a fellow fourth-grader at Mission Bell Elementary School in Jurupa Valley pulled a knife on him and threatened to "get you after school," the newspaper said. The boy, whose name was not reported, denied making the threat and student witnesses told conflicting stories about the incident.

The boy was given a five-day suspension from school, but Casteel obtained a restraining order Jan. 20, requiring the boy to transfer to another school. The father said the school's punishment was too lenient.

Casteel will seek to extend the court order for three years Wednesday.

"I want to make sure they don't put him back in the same school after the controversy dies down," he said.