Enlarge Jefferson County Sheriff's Department Video from the Columbine High School surveillance camera shows Eric Harris, left, and Dylan Klebold, carrying a TEC-9 semi-automatic pistol in the cafeteria. They later killed themselves in the library.  COLUMBINE: 10 YEARS LATER Unraveling myths: The real story behind the rampage Interactive graphic: Major U.S. incidents since 1983 Lessons from Columbine: Schools focus more on security, outreach Programs help prevent violence Review: Books get into twisted minds of Columbine killers  Enlarge Handout The 1999 yearbook photos of Eric Harris, left, and Dylan Klebold, the gunmen from Columbine High School in Littleton, Colo., that left 13 dead and many others wounded that year.  TIPS FOR MOM AND DAD Parents and even private citizens with no link to a child can help prevent school shootings, says Peter Langman, a psychologist and the author of Why Kids Kill: Inside the Minds of School Shooters (Palgrave Macmillan). Here are some of his suggestions: Set limits on your child's privacy. Keep open communication. Know your child's friends, what he does, what websites he visits. If there is a preoccupation with weapons or violent scenarios in journals, he may need help from a counselor. Pay attention to school warnings. If the school contacts you with concerns about your child's violent stories or class presentations, he may be depressed or enraged and need help. These "red flags" have been noticed by teachers before school shootings, but parents rebuffed school officials. Eliminate easy access to guns at home. Recognize possible rehearsals of attacks. Some school shooters have done drawings, animations and videos or written stories in advance that depicted brutal acts. Stay alert to possible signs of future trouble. Private citizens have foiled rampage killings by youths. Among them: a clerk in a photo shop who noticed photos of a teenager with an arsenal of guns and someone who found a notebook with plans for a high school shooting in a parking lot. If you notice a possible threat, promptly notify the police.  Enlarge CNN screenshot Patrick Ireland, who was severely wounded in the Columbine shooting, was helped out of a school window by members of the FBI.

The two teenagers who killed 13 people and themselves at suburban Denver's Columbine High School 10 years ago next week weren't in the "Trenchcoat Mafia," disaffected videogamers who wore cowboy dusters. The killings ignited a national debate over bullying, but the record now shows Eric Harris and Dylan Klebold hadn't been bullied — in fact, they had bragged in diaries about picking on freshmen and "fags."

Their rampage put schools on alert for "enemies lists" made by troubled students, but the enemies on their list had graduated from Columbine a year earlier. Contrary to early reports, Harris and Klebold weren't on antidepressant medication and didn't target jocks, blacks or Christians, police now say, citing the killers' journals and witness accounts. That story about a student being shot in the head after she said she believed in God? Never happened, the FBI says now.

A decade after Harris and Klebold made Columbine a synonym for rage, new information — including several books that analyze the tragedy through diaries, e-mails, appointment books, videotape, police affidavits and interviews with witnesses, friends and survivors — indicate that much of what the public has been told about the shootings is wrong.

In fact, the pair's suicidal attack was planned as a grand — if badly implemented — terrorist bombing that quickly devolved into a 49-minute shooting rampage when the bombs Harris built fizzled.

"He was so bad at wiring those bombs, apparently they weren't even close to working," says Dave Cullen, author of Columbine, a new account of the attack.

So whom did they hope to kill?

Everyone — including friends.

What's left, after peeling away a decade of myths, is perhaps more comforting than the "good kids harassed into retaliation" narrative — or perhaps not.

It's a portrait of Harris and Klebold as a sort of In Cold Blood criminal duo — a deeply disturbed, suicidal pair who over more than a year psyched each other up for an Oklahoma City-style terrorist bombing, an apolitical, over-the-top revenge fantasy against years of snubs, slights and cruelties, real and imagined.

Along the way, they saved money from after-school jobs, took Advanced Placement classes, assembled a small arsenal and fooled everyone — friends, parents, teachers, psychologists, cops and judges.

"These are not ordinary kids who were bullied into retaliation," psychologist Peter Langman writes in his new book, Why Kids Kill: Inside the Minds of School Shooters. "These are not ordinary kids who played too many video games. These are not ordinary kids who just wanted to be famous. These are simply not ordinary kids. These are kids with serious psychological problems."

Deceiving the adults

Harris, who conceived the attacks, was more than just troubled. He was, psychologists now say, a cold-blooded, predatory psychopath — a smart, charming liar with "a preposterously grand superiority complex, a revulsion for authority and an excruciating need for control," Cullen writes.

Harris, a senior, read voraciously and got good grades when he tried, pleasing his teachers with dazzling prose — then writing in his journal about killing thousands.

"I referred to him — and I'm dating myself — as the Eddie Haskel of Columbine High School," says Principal Frank DeAngelis, referring to the deceptively polite teen on the 1950s and '60s sitcom Leave it to Beaver. "He was the type of kid who, when he was in front of adults, he'd tell you what you wanted to hear."

When he wasn't, he mixed napalm in the kitchen .

According to Cullen, one of Harris' last journal entries read: "I hate you people for leaving me out of so many fun things. And no don't … say, 'Well that's your fault,' because it isn't, you people had my phone #, and I asked and all, but no. No no no don't let the weird-looking Eric KID come along."

As he walked into the school the morning of April 20, Harris' T-shirt read: Natural Selection.

Klebold, on the other hand, was anxious and lovelorn, summing up his life at one point in his journal as "the most miserable existence in the history of time," Langman notes.

Harris drew swastikas in his journal; Klebold drew hearts.

As laid out in their writings, the contrast between the two was stark.

Harris seemed to feel superior to everyone — he once wrote, "I feel like God and I wish I was, having everyone being OFFICIALLY lower than me" — while Klebold was suicidally depressed and getting angrier all the time. "Me is a god, a god of sadness," he wrote in September 1997, around his 16th birthday.

Klebold also was paranoid. "I have always been hated, by everyone and everything," he wrote.

On the day of the attacks, his T-shirt read: Wrath.

Shooter profiles emerge

Columbine wasn't the first K-12 school shooting. But at the time it was by far the worst, and the first to play out largely on live television.

The U.S. Secret Service and U.S. Education Department soon began studying school shooters. In 2002, researchers presented their first findings: School shooters, they said, followed no set profile, but most were depressed and felt persecuted.

Princeton sociologist Katherine Newman, co-author of the 2004 book Rampage: The Social Roots of School Shootings, says young people such as Harris and Klebold are not loners — they're just not accepted by the kids who count. "Getting attention by becoming notorious is better than being a failure."

The Secret Service found that school shooters usually tell other kids about their plans.

"Other students often even egg them on," says Newman, who led a congressionally mandated study on school shootings. "Then they end up with this escalating commitment. It's not a sudden snapping."

Langman, whose book profiles 10 shooters, including Harris and Klebold, found that nine suffered from depression and suicidal thoughts, a "potentially dangerous" combination, he says. "It is hard to prevent murder when killers do not care if they live or die. It is like trying to stop a suicide bomber."

At the time, Columbine became a kind of giant national Rorschach test. Observers saw its genesis in just about everything: lax parenting, lax gun laws, progressive schooling, repressive school culture, violent video games, antidepressant drugs and rock 'n' roll, for starters.

Many of the Columbine myths emerged before the shooting stopped, as rumors, misunderstandings and wishful thinking swirled in an echo chamber among witnesses, survivors, officials and the news media.

Police contributed to the mess by talking to reporters before they knew facts — a hastily called news conference by the Jefferson County sheriff that afternoon produced the first headline: "Twenty-five dead in Colorado."

A few inaccuracies took hours to clear up, but others took weeks or months — sometimes years — as authorities reluctantly set the record straight.

Former Rocky Mountain News reporter Jeff Kass, author of a new book, Columbine: A True Crime Story, says police played a game of "Open Records charades."

In one case, county officials took five years just to acknowledge that they had met in secret after the attacks to discuss a 1998 affidavit for a search warrant on Harris' home — it was the result of a complaint against him by the mother of a former friend. Harris had threatened her son on his website and bragged that he had been building bombs.

Police already had found a small bomb matching Harris' description near his home — but investigators never presented the affidavit to a judge.

They also apparently didn't know that Harris and Klebold were on probation after having been arrested in January 1998 for breaking into a van and stealing electronics.

The search finally took place, but only after the shootings.

Meticulous planning

What's now beyond dispute — largely from the killers' journals, which have been released over the past few years, is this: Harris and Klebold killed 13 and wounded 24, but they had hoped to kill thousands.

The pair planned the attacks for more than a year, building 100 bombs and persuading friends to buy them guns. Just after 11 a.m. on April 20, they lugged a pair of duffel bags containing propane-tank bombs into Columbine's crowded cafeteria and another into the kitchen, then stepped outside and waited.

Had the bombs exploded, they'd have killed virtually everyone eating lunch and brought the school's second-story library down atop the cafeteria, police say. Armed with a pistol, a rifle and two sawed-off shotguns, the pair planned to pick off survivors fleeing the carnage.

As a last terrorist act, a pair of gasoline bombs planted in Harris' Honda and Klebold's BMW had been rigged apparently to kill police, rescue teams, journalists and parents who rushed to the school — long after the pair expected they would be dead.

The pair had parked the cars about 100 yards apart in the student lot. The bombs didn't go off.

Looking for answers at home

Since 1999, many people have looked to the boys' parents for answers, but a transcript of their 2003 court-ordered deposition to the victims' parents remains sealed until 2027.

The Klebolds spoke to New York Times columnist David Brooks in 2004 and impressed Brooks as "a well-educated, reflective, highly intelligent couple" who spent plenty of time with their son. They said they had no clues about Dylan's mental state and regretted not seeing that he was suicidal.

Could the parents have prevented the massacre? The FBI special agent in charge of the investigation has gone on record as having "the utmost sympathy" for the Harris and Klebold families.

"They have been vilified without information," retired supervisory special agent Dwayne Fuselier tells Cullen.

Cullen, who has spent most of the past decade poring over the record, comes away with a bit of sympathy.

For one thing, he notes, Harris' parents "knew they had a problem — they thought they were dealing with it. What kind of parent is going to think, 'Well, maybe Eric's a mass murderer.' You just don't go there."

He got a good look at the boys' writings only in the past couple of years. Among the revelations: Eric Harris was financing what could well have been the biggest domestic terrorist attack on U.S. soil on wages from a part-time job at a pizza parlor.

"One of the scary things is that money was one of the limiting factors here," Cullen says.

Had Harris, then 18, put off the attacks for a few years and landed a well-paying job, he says, "he could be much more like Tim McVeigh," mixing fertilizer bombs like those used in Oklahoma City in 1995. As it was, he says, the fact that Harris carried out the attack when he did probably saved hundreds of lives.

"His limited salary probably limited the number of people who died."

Contributing: Marilyn Elias, USA TODAY