Seven years later, Harriet Hall still isn't sure what caused Eric Harris and Dylan Klebold to go on their deadly rampage at Columbine High School. She does believe the nation is better prepared to deal with such violence.

"We are sadder and wiser," said Hall, the lead counselor for victims of the massacre that left 13 people dead.

Authorities on Thursday released nearly 1,000 pages of new documents from the massacre, including essays, school work and computer files from Klebold and Harris, the two suicidal killers.

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The papers included their step-by-step plans as they gleefully plotted the deadliest school attack in U.S. history. It also included a journal kept by Harris' father that referred to his son's disciplinary and psychological problems but shed no light on whether he knew the teen might be capable of the slaughter.

"Hell on Earth — ahh, my favorite," Klebold wrote in Harris' 1998 yearbook above a drawing of a gun-wielding headless soldier. "So many people need to die."

The Denver Post sued to force the release of the 936 pages. The Colorado Supreme Court left the decision up to the sheriff's office, and the Harris and Klebold families did not challenge the decision.

More than 20,000 documents and videos have been released since the attack. The sheriff has refused to release videotapes made by the gunmen, concerned they would encourage copycat attacks. Some of the details revealed Thursday were disclosed previously.

Still, the new material offers a chilling insight into the killers in the months before the attack. They had "to do" lists, with each purchase of a gasoline or a weapon marked off, and they had a hit list with at least 42 entries (all redacted).

"Once I finally start my killing, keep this in mind, there are probably about 100 people max in the school alone who I don't want to die, the rest MUST (expletive) DIE!" Harris writes in a journal entry from October 1998, six months before the attack.

The pages are filled with profanity, racial slurs and drawings depicting violence or death. A scrawled entry in a Klebold day planner apparently sketches out April 20, 1999, down to the minute, starting with a 6 a.m. meeting, a 10:30 a.m. "set up," an 11:12 a.m. "gear up" and at 11:16 a.m., "HAHAHA."

Remarking on the possibility that the two might survive, Harris wrote they would try to escape to a foreign country where they couldn't be extradited. If not, they'd crash a plane into New York City with them inside.

The material also includes Wayne Harris' journal with entries addressing threats made by his son against classmate Brooks Brown more than a year before the attack. The Brown family reported the threats in early 1998 and still contends the authorities or the Harrises should have taken action against the boy.

"We feel victimized," Wayne Harris wrote. "We don't want to be accused every time something happens. Eric is not of fault. Brooks Brown is out to get Eric. Brooks had problems. ... manipulative con artist."

Wayne Harris' attorney did not return a call seeking comment.

Brown said Eric Harris had "lied about everything to his father and made him believe he was innocent and everyone else was the evil party."

Brown's father, Randy Brown, said the sheriff's office should release everything, including the videos and audiotapes from the killers.

"There are lessons to be learned," the elder Brown said. "This information will be hidden forever. They are trading their cover-up for the lives of children in other schools."

Hall, the counselor, said many of the lessons have already been learned.

"Our best practices for how you respond has changed and a lot of that happened because of Columbine," she said.

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