CLEVELAND (AP) _ A fifth white student pleaded innocent Friday in what authorities say was a plot to mimic the Columbine High School massacre at their predominantly black high school.

The boy was arrested Thursday after police searching his home found guns, Assistant Prosecutor Doug Weiner said. The boy's attorney said the weapons were his grandfather's hunting guns.

Four other teens, one 14 and the others 15, pleaded innocent Sunday.

All five are in custody and charged with delinquency by reason of conspiracy to commit murder and juvenile counts of inducing panic, inciting to violence and possession of criminal tools.

If convicted, they could be confined until age 21.

Authorities said the students were planning to plant bombs in the school and gun down their teachers and fellow students.

Mayor Michael White closed South High School Oct. 29 after authorities uncovered the plot, which he said appeared to be racially motivated. No bombs or guns were found, and the 1,500-student school reopened Monday under tight security.

Six other students have been questioned by police and suspended from school.