To critics, the documents are more proof that warning signs were ignored.

"Your first reaction is to say, 'What if all these people had called the police?"' said parent Judy Brown, who warned police a year before the shootings that Harris boasted on the Internet of wanting to kill people. "Well, we did call the police. And they didn't do their job."

But others who knew the shooters said what people might consider warning signs seemed at the time like innocuous teen-age angst.

Alyssa Sechler, who took German class with Harris, told investigators he included a drawing of a guy holding a gun with a note in her yearbook.

She told investigators she knew Harris did not like jocks, "but she just thought it was hot air."

The reports include new details on what Harris and Klebold allegedly told their co-workers at Blackjack Pizza, a neighborhood hangout where they boasted of bomb-making and made contacts to obtain guns.

Former delivery driver James Brian Thornby II told investigators about a conversation with Harris in early 1999.

"Eric had just gotten a $300 paycheck and said he had seven propane tanks and wanted to get nine more with the paycheck he had gotten," Thornby said. "And he wanted to have 30 in all by a date, I guess it was the 20th."

"I think he said it was Hitler's birthday," Thornby clarified.

"He said he wanted to blow up the school, but he didn't say he was gonna do it," Thornby said. "I just thought he was like, you know, someone pissed off, talking."

At the school, Klebold's writings were prescient of violence.

In February 1999, he turned in an English class essay about the man in a black trench coat who systematically mows down a row of college prep students and then sets off an explosion miles away to divert police.

He describes the man as resembling God: "The man smiles, and in that instant, through no endeavor of my own, I understood his actions."

"Good details," teacher Judy Kelly wrote in the margins, but she also questioned his use of profanity, spoke with Klebold, his parents and a guidance counselor.

It was just a story, Klebold said.

In an economics class, Harris and other students were asked to make a marketing video for a make-believe product or service.

Harris got Klebold's help on a video showing the teens with guns in the school and German rock music playing in the background. Harris' service? A hit man "nerds" could call to knock off school bullies.

One investigative report includes the hindsight of a prospective teacher who claims to have overheard a troubling conversation in a hallway the day before the school shootings.

The teacher, whose name couldn't be verified Tuesday, said she was on her way to a job interview with Columbine Principal Frank DeAngelis when she heard a group of students in long coats talking about blowing something up the following day.

Investigators asked DeAngelis if he, as they had been told, went out to quiet down the boisterous group. DeAngelis said he did not remember the incident but said the job candidate told him the story weeks after the shootings.

Other school officials saw something in the two shooters but never put their finger on the potential danger.

Dean of Students Peter Horvath knew Klebold and Harris. One of the first times he doled out punishment at the school was after the pair got caught hacking into the school's computer system to steal locker combinations in 1997, he told investigators.

Horvath described Harris as shy, Klebold as mature and outspoken, calling both "brilliant kids." They never complained to him about being harassed — and never drew complaints from other students.

But in the end, Horvath said he was not shocked about what they did. He had seen the potential for their "evil side."

The documents are riddled with encounters that now seem sinister.

Rebecca Heins, who had class with Harris and Klebold and Brooks Brown, said Harris and Klebold would jokingly ask each other, "Can I shoot that guy?"

Chris Morris, a friend of both Klebold and Harris, told investigators that his girlfriend observed Harris and Klebold in the Columbine cafeteria a few weeks before the shootings. They were looking over a piece of paper. When she asked what they were doing, they tried to keep it away from her.

She grabbed the paper from them and saw it included a diagram of the school cafeteria, along with a location of the cameras.

On the day of the shootings, student Melissa Walker dragged her wounded friend, Stephanie Munson, from the school. Later, Walker was troubled by an ominous warning from Harris.

Four days before the attacks, she was in the computer lab and asked Harris about the initials on his baseball hat: KMFD, the name of a German rock band.

Walker asked if the initials stood for a radio station. Harris thought she was teasing him and took offense.

He answered: "You just wait and see."

Contact M.E. Sprengelmeyer at (303) 892-2741 or sprengelmeyerm@RockyMountainNews.com. Contact Michele Ames at (303) 892-2327 or amesm@RockyMountainNews.com.