Los Angeles - Minnesota authorities on Friday filed papers to charge a Minnesota minor as an adult after his arrest for allegedly planning Columbine-like plot to bomb his school and kill his family, the Minneapolis Star Tribune reported.

John David LaDue, 17, of Waseca, was arrested on Tuesday after a witness reported a suspicious person at a rental unit.

In the storage unit police found materials for making explosive devices, and at the teenager's home they discovered a stash of handguns, automatic weapons and completed bombs.

In a 180-page journal LaDue allegedly described his plans to murder his sister and parents and then attack the Waseca Junior and Senior High schools with a pressure cooker-type bomb and Molotov cocktails to kill “as many students as possible,” the Los Angeles Times reported citing a criminal complaint.

LaDue was charged on Thursday as a juvenile with four counts of attempted murder, two counts of first-degree damage to property and six counts of possession of a bomb by someone under age 18. Police said, LaDue wanted to carry out his attack on April 20, the anniversary of the Columbine shooting - he allegedly idolised the Columbine killers - but changed his plan because the school was closed for Easter Sunday that day, WCCO-TV reported. - Sapa-dpa