A teenager has pleaded guilty to plotting a Columbine-style attack on his northern Indiana high school, authorities said.

The 16-year-old Penn High School student entered the plea to the juvenile charges on Wednesday before a magistrate, who set a July 8 sentencing date.

He was accused of planning the attack with an Ohio man.

The teen was arrested April 19 and charged with a juvenile count of conspiracy to commit murder after a school officer investigating an unrelated threat at the school discovered Internet postings in which the teen allegedly discussed his support for the Columbine attack.