Columbine shooters | Eric Harris | Wayne Harris diary
Two years before the shootings, Eric's father Wayne Harris started keeping a log of Eric's erratic behavior. In this 60-page spiral notebook he recorded Eric's altercations with his friends and his run-ins with the legal system. In 1997, following the blow-up between Eric and Brooks Brown, Wayne described feeling victimized by the Browns after his son broke Brooks' windshield. On April 19, 1997, he claimed the Browns were out to get Eric; that the complaints that they had about Eric were not his son's fault despite evidence to the contrary.

A September 21, 1998 assignment that Eric submitted at school was on the theme: "When it was bad to be good". In it, he wrote about how he had to turn over all of his stockpiled weapons to his parents. "It was bad not because I might use the weapons, just because I paid good money or spent a lot of time making them. It made me feel that all that time and money was wasted. But since weapons are dangerous and my parents didn’t trust me, I suppose it was for the better."

Toward the end of his journal, Wayne writes about how he had to impose additional rules on his son because Eric was unwilling to control his sleep and study routines. He had to limit Eric's television, phone, and computer time. He instituted a "lights out at 10 p.m." rule as well. He knew Eric had broken into a van and stole things out of it in January 1998. He also knew Eric was messing around with bombs: Wayne himself had disposed of a pipe bomb he had found in his son's room just months before the shooting. Nate Dykeman said in an interview (archived offsite link) with Good Morning America that the Harrises didn't report it to the authorities because Eric was in juvenile diversion for the break-in at the time.

Even still, the day of the shootings, Wayne Harris told police investigators that he had no reason to believe his son would be involved in such a shooting.