By David Bailey
MINNEAPOLIS, May 1 (Reuters) - A southern Minnesota teenager who idolized a gunman from a Colorado high school massacre was charged Thursday with planning to kill his parents and sister and then slaughter students and staff at his school, authorities said.
John David LaDue, 17, laid out his plans in an extensive journal and amassed bomb-making materials including gun powder and ball bearings as well as firearms and ammunition, Waseca, Minnesota police said.
"We believe that LaDue planned to carry out his attack within the next few weeks," Waseca Police Captain Kris Markeson told a news conference.
LaDue's journal had references to school shootings such as that at Columbine High School in Littleton, Colorado, where two students killed 13 people and themselves in 1999, a criminal complaint said. He idolized one of the Columbine gunmen and critiqued what he thought they had done right or wrong during their attack, it said.
LaDue told police he had wanted to carry out his attack on April 20, the 15th anniversary of the Columbine massacre, but could not because it was Easter Sunday, the complaint said.
The plot was thwarted when someone called police Tuesday night after seeing a suspicious person carrying a backpack enter a storage unit and close the door behind him in Waseca, a town about 65 miles (105 km) south of Minneapolis, Markeson said.
Police encountered LaDue and saw bomb-making materials at the unit, Markeson said. Police searched the unit and at his family's house found firearms, ammunition, prepared bombs and the papers documenting his plans, Markeson said.
He was charged as a juvenile with four counts of attempted first degree murder, two counts of first degree attempted criminal damage to property and six counts of possession of an explosive or incendiary device by a person under age 18.
LaDue remains in custody and was identified because of the severity of the charges and because he is over age 16.
He had planned to kill his family, set a fire in rural Waseca to distract authorities and then head to the building that houses Waseca's junior and senior high schools, with more than 900 students, Markeson said.
Based on LaDue's account to police and his journal, he planned to set off numerous bombs during lunch, kill a school resource officer as he responded to help, then set fires and shoot students and staff before being killed by law enforcement officers, Markeson said.
Markeson said the investigation would take several more weeks. (Reporting by David Bailey; Editing by Sharon Bernstein and Cynthia Osterman)