WASECA (AP) - The teenager accused of planning to kill his family and carry out a massacre at the Waseca high school told police no one noticed he was mentally ill and that he was trying to hide it.

In newly released audio recordings of police interviews, the 17-year-old calmly describes his plans to "dispose of" his family, set a fire as a diversion and then use explosives and guns to attack his school. The Star Tribune says the teen tells an officer he thought it would be "fun" and he would be following his idol, Columbine gunman Eric Harris.

The teen is charged in juvenile court. He was arrested in April after authorities said they found him in a storage locker with bomb-making materials. His father says he doesn't believe his son would have actually carried out the attack.