Detective Kate Battan walked into a small office, carrying three videotapes.

The tapes, with perhaps three hours of footage, had been confiscated from the home of Eric Harris.

Battan, lead investigator in the Columbine High School shootings about 10 days earlier, dimmed the lights.

Up popped the young killers on the television screen, cocky and confident.

The teen-agers sat on a couch speaking into the camera, weeks before their murderous assault.

There was no doubt whom the boys were addressing. They kept referring to "you detectives."

We're doing this alone, they said, again and again.

And they made another point: They had begun planning their rampage long before the spate of school shootings across the country.

We're no copycats, they said. Those other kids? They're copying us.

If their boasts were true, their plan to assault Columbine had started more than two years earlier -- before the shootings in Springfield, Ore.; Jonesboro, Ark.; West Paducah, Ky.; and Pearl, Miss.

The Series

Sunday: The first fragmentary reports of shooting at Columbine bring more than 600 police officers face to face with the unthinkable.

Monday: After 48 chaotic hours, specialists from a dozen agencies are organized into teams to launch a methodical examination of the crime.

Today: As they near the end of eight months of intensive work, investigators still grope for an answer to the biggest question of all.

The images and voices of the boys stunned Battan, an investigator who had moved in recent years from complex, white-collar and financial crimes to high-profile homicides.

In 1998 alone, the sheriff's detective had been involved in two of the most sensational cases in Jefferson County history -- the murder of two children by their mentally ill mother and a triple ax-slaying at a townhome over Fourth of July weekend.

But now, months later, even that experience couldn't ease the horror that eneveloped her in the darkened room as she watched Harris and Dylan Klebold speaking, it seemed, directly to her from the grave.

The images spooked Battan so much she turned the lights back up before the tapes finished.

"It just flabbergasted me," she says, "that so much evil came out of these two teen-age boys."

The release this week by Time and the Denver Rocky Mountain News of printed excerpts of the videotapes gave the public a detailed glimpse at the criminal minds of the two killers. But the printed words don't convey the cold, calculating tone of the boys' voices.

In their soliloquies, Harris and Klebold thanked two friends who had helped them get the semiautomatic pistol they'd used at Columbine. The boys urged investigators not to press charges against the two.

"If they wouldn't have f------ helped us out, then we would have found someone else," Harris bragged. "We would have gone on and on. We would have found some way around it, 'cause that's what we do."

In the months ahead, Battan would come to see this as the quintessential philosophy of the two boys: "That's what we do."

"That," Battan says, "is Eric Harris and Dylan Klebold."

Guns and Bombs

For explosives specialist Doug Lambert of the federal Bureau of Alcohol, Tobacco and Firearms, Columbine was everything he'd ever trained for. His job was simple: make sure more bombs weren't planted in the school.

Two of Lambert's colleagues were unlike any others.

Jenny and Cascade, Labrador retrievers from Virginia, were specially trained to sniff out chemicals found in bombs and bullets. ATF agents used them to check each locker, air duct, ceiling and backpack.

The agents examined the scores of bombs -- exploded and undetonated -- found inside the school. They used a computer program to map where fragments were recovered.

"We basically put all the pieces back together again," says Jerry Petrilli, head of the ATF's firearms group in Denver.

Local bomb experts defused those that didn't explode.

As they went, ATF agents cautiously packaged each device -- or what was left of it.

But flying the mass of material to the ATF's national bomb laboratory in Walnut Creek, Calif., was too dangerous. Instead, agents loaded the bombs into a light brown Ford Explorer and drove them to California.

On the scene for more than a week, Lambert came away thankful that Harris and Klebold knew little about building bombs.

They didn't understand explosive reactions. They didn't understand electrical circuitry.

None of the four bombs wired with timing devices -- two in the cafeteria and devices in the killers' cars -- exploded as planned.

The Killers' Suppliers

While bomb experts unraveled explosives evidence, ATF agent Marcus Motte and other investigators tracked the guns.

Investigators, talking to everyone who knew Harris and Klebold, quickly determined how the guns got into the killers' hands.

Three days after the killings, two ATF agents met with Nate Dykeman, an 18-year-old friend of Harris and Klebold.

Dykeman provided some of the first clues to the path of the guns, telling investigators that two weeks before the shootings, he'd seen Harris with a videotape in one of their classes at Columbine. The tape showed Harris and Klebold firing guns at a shooting range in the mountains.

Also on the tape, Dykeman related, were scenes showing Philip Duran, 22, and a friend of his named "Mark" firing two shotguns. Duran worked with Harris and Klebold at a Blackjack Pizza parlor about a mile from the high school.

Two days later, Motte interviewed Duran.

Duran told the ATF agent that Harris and Klebold had approached him in January, eager to buy a gun. Duran gave them the phone number of a guy he knew named Mark Manes.

Duran said he collected money from Harris and Klebold and gave it to Manes as part of the sale of a TEC DC-9 9 mm semiautomatic pistol, a gun Klebold fired 55 times at Columbine, killing four and wounding two. It was also the gun that ended his life.

After the shootings, realizing Harris and Klebold had used the gun he'd sold at Columbine, Manes hired an attorney and decided to cooperate with investigators.

On April 30, on the sixth floor of the Federal Building in downtown Denver, Manes and his attorney met with Motte and other investigators.

Manes told them he had purchased the weapon at a 1998 gun show and acknowledged that he'd been introduced to Harris and Klebold by Duran.

Manes said he sold the gun to the killers on Jan. 23 for $500.

Manes was sentenced Nov. 12 to six years in prison for selling the gun to Klebold and Harris and for firing a sawed-off shotgun with them weeks before the massacre. Duran faces similar charges.

Investigators also tracked two shotguns and a carbine from Harris and Klebold to Robyn Anderson, 19. She'd been Klebold's prom date three days before the attack.

But Anderson, who admitted buying the three guns for Harris and Klebold at the Tanner Gun Show in Denver, has not been charged.

Federal law prohibits the "straw purchase" of a firearm on behalf of someone who is ineligible to buy it. The two killers were underage.

But the law applies only to guns sold by a licensed federal firearms dealer. ATF agents have determined that Anderson bought two of the three guns from a private person -- not a dealer. But they have not found who sold Anderson the third gun.

If that person turns out to be a licensed dealer and Anderson falsified documents to disguise the purchase, she still could face charges.

The Library Team

As Arvada police detective Russ Boatright took his team into the school library for the first time, technicians were still photographing, cataloging and collecting debris.

"We actually had an idea of what happened before we went in there," he says. "But it doesn't actually hit you until you see it."

At 40, Boatright had been a cop for more than 17 years. He'd seen plenty of misery, including crimes against children.

But the blood-spattered room stunned even him.

At first, he could not imagine the terrifying minutes in the library on April 20 -- smoke choking the air, a fire alarm blaring, strobe lights flashing, gunshots ringing out, one after another.

But soon it would become painfully real to him.

Boatright's team had the benefit of one incredible piece of evidence -- the tape of a 911 call made by Patricia Nielson, a teacher Harris wounded. She'd been shot near the school's west doors, where the gunmen entered, then had crawled to the library and grabbed a phone.

Despite the wail of the fire alarm, investigators were able to enhance the tape.

What they retrieved was an audible record of terror, one gunshot at a time. The tape showed that the shooting in the library was over in 71/2 minutes.

Starting with a rough sketch, investigators asked the 40 kids and four teachers who had survived the library massacre to draw in their recollections.

Boatright kept track of the developing story with color-coded markers -- red for the dead, blue for the wounded, green for the survivors who escaped physically unharmed.

The FBI sent experts to Columbine from Virginia to construct an elaborate model of the school. They took back rough drawings and detailed measurements.

They returned in midsummer with a diorama of the cafeteria and the library above it. It was exact -- down to the bookshelves that divided the library into three sections and the trees standing outside.

Boatright's team started interviewing everyone.

"Nobody saw everything from A to Z," he says.

The physical barriers in the room -- bookshelves and desks -- and the terror accentuated the reality that no two people ever see an event exactly the same way.

It reminded Boatright of a collage that hangs in a hall at Columbine.

A teacher assigned students to photograph a tree. Each kid snapped pictures from various angles. When they put all the pictures together, the composite image depicted the entire tree, each slice a different size, from a different perspective.

To clear up the inconsistent library accounts, the team launched an excruciating process -- taking the survivors back inside.

For the traumatized kids and their parents, it was an appalling scene: dried blood on the floor and walls, name tags marking the spots where students fell.

The investigators asked the survivors to crawl back under the tables where they had ducked for cover. Then they joined them, on hands and knees, to see it how the survivors had seen it.

One of the most noted episodes in the library had been a reported exchange between student Cassie Bernall and one gunman.

"Do you believe in God?" the gunman asked.

"Yes, I believe in God," Cassie replied.

"Why?" the gunman said, then pulled the trigger.

But student Emily Wyant, who had crouched under a table beside Bernall, told investigators the conversation never happened.

Later, with student Craig Scott, who'd escaped from underneath a table where two classmates died, investigators' doubts grew.

Scott is the brother of Rachel Scott, who had been killed outside the school. He had been a few feet from Cassie and thought it was her voice he heard.

But when he revisited the library, he realized the voice had come from another direction -- from the table where student Valeen Schnurr had been shot.

Investigators came to believe it was probably Valeen, who survived, who told the gunman of her faith in God.

Reconstructing events in the library drained Boatright and his team. They gradually realized how vulnerable everyone had been that day.

"When you see the room, you see that no one was really hiding," Boatright says.

One question could not be answered: How did Harris and Klebold pick their victims?

Under one table, they'd gun down two kids, only to leave a third physically unscathed.

"None of it makes sense," Boatright says. "Realistically, they could have gone through that library and shot every single person."

The Cafeteria Team

When investigators filed into the cafeteria Harris and Klebold had planned to incinerate, its floor was still soggy from sprinklers that sprayed for hours after the fire alarms sounded six days earlier.

A musty stench hung in the air. Food cluttered the tables; 450 backpacks littered the room.

Nine-year FBI veteran Rich Price and his 25-member crew started to identify every student who had been in the cafeteria. A list provided by the school district indicated each student who had an A-period lunch hour. But many of them had gone home or to restaurants to eat.

Investigators went from one student to another. Each would give them a new handful of names to track down.

Some visits would last 15 or 20 minutes, others hours.

Just as it had in the library, technology gave a helping hand.

The surveillance camera in the lunchroom captured the arrival of Dave Sanders, the teacher who was fatally wounded minutes later. It also recorded the exodus of the students, and -- finally -- the arrival of Harris and Klebold.

By the time they were finished, investigators had developed a seating chart that placed everyone in the cafeteria, exactly where they were when shots rang out.

"It was like dropping 700 toothpicks -- give or take -- and putting them back in the box, exactly the way they were," Price says.

The Computer Team

In a laboratory off Kipling Parkway in Lakewood, in what looks like the back room of a computer repair shop, Colorado Bureau of Investigation computer expert Chuck Davis went to work.

Behind a locked door, shaded by drawn blinds, Davis and his investigators analyzed the computers seized from the Harris and Klebold homes and elsewhere, tracing their data, uncovering their digital secrets.

Davis was well-suited to the job. When he joined the CBI four years earlier, he became the first investigator outside the Internal Revenue Service and the military to look at computer crime in Colorado.

Just hours after the Columbine killings, Davis went to Harris' home, where detectives seized the killer's computer. It became evidence item No. 001.

In the next few weeks, the team confiscated 18 other computers and 5,000 disks, most from friends of the killers. Three of the computers were taken from Columbine High: the school's main server and two machines in the media laboratory where Harris and Klebold often worked.

They pored over e-mail among Harris and Klebold and friends. Most of the writings spoke only of teen-age concerns. Girls. Games. Television shows.

The investigators scrutinized Web postings and other writings -- some from Harris' computer -- promising more death on April 26, a threat that never materialized.

Unlike Harris' computer, Klebold's offered no help.

Investigators concluded that Klebold had gutted the machine, erasing one of the two hard drives, leaving it blank.

"I can't prove it," Davis says. "But deep down in my heart, I think it was probably nuked either the day before, or that morning."

What did Klebold have to hide?

"We'll just never know," Davis says.

Investigators concluded that other computers probably were tampered with after April 20 and before they were seized.

They found scores of Internet and e-mail threats related to Columbine -- everything from "I was there and helped shoot the kids" to "There are pipe bomb instructions at this Web site."

They tried to track down what they dubbed a "master school bombing list" only to discover it didn't exist.

When a kid in New York posted an Internet message claiming that he'd been at Columbine, cops kicked in his door and took his computer.

"We took it seriously," Davis says. "I like to think cops have a sense of humor, but when you're dealing with a bunch of dead kids, our humor factor was zero."

The computer team found no evidence to suggest that anyone knew about the macabre plans of Harris and Klebold -- or helped carry them out.

But the investigators destroyed a myth:

Harris and Klebold weren't the computer experts they had been made out to be. They were good, Davis says, but other kids could do much more.

The Outside Team

In the moments before Harris and Klebold began their assault, some students had dropped their backpacks and gone outside to play on the soccer field. Some had left campus. Others took advantage of the sunshine to have lunch on the grass.

Mike Barnett's team eventually identified 100 witnesses outside the school, not including law enforcement officers.

"The main thrust was to interview witnesses to determine the sequence of events," the FBI agent says. "Who was where, who shot whom, who did what."

To do that, the team turned to the FBI's special projects unit on the East Coast. They developed a four-foot-by-five-foot, computer-generated schematic with plastic overlays locating all the outside witnesses, victims and police, and what they had seen.

They tracked down school janitors and maintenance workers from Clement Park next to the school. They found people who had walked past the school or through the parking lots that morning.

And they waited patiently for the chance to interview those who were seriously wounded.

Some witnesses had seen Harris and Klebold arrive in the parking lot. But no one had seen them carry two large duffel bags inside minutes later and set them down in the cafeteria.

Barnett and his team discovered, through sales receipts, that Harris and Klebold had filled the two large propane tanks for their cafeteria bombs the morning of the attack.

The Outside Team also interviewed every police officer outside the school that day, including sheriff's deputies Paul Smoker and Neal Gardner, who briefly traded shots with Harris and Klebold. Team members also interviewed nine other officers who fired their weapons at Columbine on April 20.

The investigators dispelled several claims by witnesses, including one about a rooftop sniper.

The man on the roof, it turned out, was an air conditioning repairman who quickly hid when the shooting started. He saw virtually nothing.

The Friends and Associates Team

The day of the shootings, television crews captured video of three young men in a field near the school. They were wearing military fatigues and walking toward the scene. Police with bulletproof vests and shotguns handcuffed them and led them away.

"Let the media chase those guys," said sheriff's Sgt. Don Estep, who soon took charge of the Friends and Associates Team.

After 27 years as a Jeffco sheriff's deputy, much of it in the shadowy world of undercover intelligence, Estep knew almost by instinct that the young men probably weren't involved. He was right. Investigators quickly eliminated the three as potential suspects.

But ruling out other suspects, those who were friends or associates of Harris and Klebold, would be far more difficult.

The team was confronted by reports that as many as eight gunmen had been in the school. Some witnesses reported seeing someone besides Harris and Klebold firing a weapon inside.

There also were dozens of tips that Harris and Klebold had help carrying pipe bombs into the school and possibly planning the attack.

Investigators visited the homes of witnesses and potential suspects.

They kept hearing the same things about Harris and Klebold: They were smart, they were partners and they kept most of their business -- especially their plot -- to themselves.

To verify alibis, investigators asked several friends of Harris and Klebold to take polygraph tests.

"We certainly used the lie detector as a tool to clear individuals of involvement in this," says Mark Holstlaw, an FBI agent who worked closely with Estep on the team. "Some agreed, some declined, some had their own done. For those who declined, we used other investigative methods to clear them."

Speculation about additional suspects continued for weeks.

One Denver television station repeatedly showed videotape of a friend of the gunmen being put into the back of a squad car by police on April 20. The reports implied that arrests of co-conspirators were imminent.

But except for Manes and Duran, no other arrests came.

The Threats Team

Sgt. Rich Webb, a 24-year law enforcement veteran, missed the first hours of Columbine. April 20 was his day off, and he was in his back yard, landscaping. When sketchy reports of a shooting at Columbine interrupted music he was listening to, he called the office.

"This is bad," he was told. But a supervisor told him to stay home and rest. We'll need fresh people tomorrow.

Webb, a former SWAT team leader, grumbled and threw rocks around his yard the rest of the afternoon. The biggest case of his career and he was out of the loop.

But not for long.

He spent the next two days working with the coroner to identify the dead and assist with autopsies.

By the time he moved onto the Threats Team six days after the shootings, menacing messages were pouring in. From the Internet. From the phone. From other schools in the area.

At a middle school in Arvada, a student trying to be funny left what looked like a bomb in a bathroom. He had wrapped a plastic box in aluminum foil and taped nails to it.

At an Arvada high school, a woman angry about her son's treatment by athletes phoned in a threat.

In Broomfield, a boy sent a threatening e-mail to the Columbine memorial organization.

Webb's team tracked them all down.

Some threats actually were innocent statements that eventually took on a sinister tone.

One happened at Chatfield High, where many of the emotionally fragile Columbine students were finishing the school year.

"You could bring something into this school," one kid told another, emphasizing what he saw as a lack of security.

Someone overheard the remark. Then it was repeated, again and again.

By the time Webb's team heard it, two kids were plotting to bring in weapons and bombs.

The investigators sped to Chatfield. As they rushed in, they found hallways packed with frightened students.

"The panic was ready to go," Webb says. "These kids were on edge ... ready to go out that door. Somebody could have snapped their fingers loudly and those kids would have bolted."

Much of the Threats Team's work was tracking information to its original source.

"We would run from rumor to rumor to rumor," Webb says.

After two weeks of chaos, leads began to taper off. By the time the team finished, it had investigated 202 threats.

The threats led to six arrests in the United States and Canada. Eleven students were suspended from school -- nine in the Denver area, including six from Columbine.

Along the way, investigators encountered scores of kids who bragged that they were in the Trench Coat Mafia. They found other kids who sympathized with Harris and Klebold and admired their anti-social lifestyle.

"It was just absolutely bizarre," Webb says. "You had to stop and ask, 'What in the world is he talking about?"'

Investigators' aggressive response to the loose talk sometimes crashed head-on into concerns over the right of free speech. Some cops found it disturbing that people could write anything in support of two teen-agers so full of hate that they planned -- as U.S. Attorney Tom Strickland put it -- "to become the biggest mass murderers in United States history."

On Their Own

As months wore on, detectives focused not only on what happened at Columbine, but on what didn't happen.

After analyzing more than 3,500 pieces of evidence, from bullets and spent shell casings to blood and fingerprints, Colorado Bureau of Investigation technicians ruled out one fear -- that some victims might have been hit by "friendly fire" from police guns.

They also ruled out the existence of a third gunman.

Many detectives had believed from the start that Harris and Klebold had acted alone.

Confirmation came in late July with the CBI's final ballistics reports.

Every bullet or fragment matched one of the four guns used by Harris and Klebold or weapons fired by police.

Only one conclusion could be drawn: There was no third gunman.

But ballistics evidence could not answer other key questions.

Had anyone known that Harris and Klebold planned to attack the school on April 20. Had anyone helped?

No evidence supported either possibility.

"Are you ever completely sure?" asks FBI agent Dwayne Fuselier, an anti-terrorism specialist who helped run the investigation. "Maybe not. Could something surface in the future? I suppose. But I think I would say this, we're about 99.9 percent sure."

Drawing conclusions

Police finally got their long-awaited interview with the parents of Eric Harris in October. It came after months of quiet negotiations between the family's attorneys and District Attorney Dave Thomas.

Beforehand, investigators agreed with the Harris family and their attorneys not to say anything publicly about the discussion. They were similarly silent about their interview, 10 days after the killings, with Dylan Klebold's parents.

Now, almost eight months after their work began, here's what Columbine investigators have concluded:

Only Harris, Klebold and police fired weapons inside the school.

No one helped the killers carry bombs into the school.

The terror was relatively short-lived -- roughly 16 minutes from the first gunshot outside the school about 11:20 a.m. to the last one in the library.

Harris and Klebold probably were dead shortly after noon -- though that point is still open among investigators. What is known is that between the time they left the library around 11:36 a.m. and returned there to commit suicide, they didn't shoot anyone else.

There is no evidence of a wider Columbine conspiracy.

In fact, evidence pointed the other way. The massacre was carried out by two intelligent, secretive, cunning teen-agers who managed to keep their terrible plot to themselves.

Not everyone was convinced. Sheriff John Stone still harbors doubts.

"You'll always wonder if somebody else was involved," he says.

Despite the questions that remain, the Columbine investigation succeeded in one way no one really had foreseen: The multiagency task force became a model for other communities across the country.

"Basically, they (officers) left their badges and their egos at the curb," CBI Inspector Pete Mang says. "I've never seen that in law enforcement before."

Investigators still wonder why.

"It may have been because this thing was so big that everyone had their own piece of it," Estep says. "There was plenty of work to go around."

The nature of the event and the age of the victims also may have convinced investigators that turf battles would be pointless, unprofessional and insensitive.


In a tiny, stifling interrogation room, sheriff's Sgt. Randy West shifts uncomfortably in a gray plastic chair.

He clears his throat, crosses his legs, takes a deep breath. Now and then, tears well in the corners of his eyes, evidence of the stress of months of investigating the inexplicable tragedy at Columbine.

West, 41, is accustomed to asking questions in this room. But now, he is answering them.

This is how it was, he says, behind the closed doors of the most complex criminal investigation in Colorado history.

And this is the toll it took.

He recalls the day he realized how close two teen-agers came to accomplishing even more heinous devastation -- killing hundreds of students in the school cafeteria with two large bombs that, for some reason, failed to explode.

"I don't know why they didn't go off, and I don't care to know," West says.

A stricken look freezes on his face.

"It would have been worse than Oklahoma City. Much worse. I don't even want to think about that."

But day after day, for months, West and his fellow investigators have thought of little else.

The devastation of families, caused by two teen-age boys, the grief, the horror, the impact on investigators themselves, have all come to rest like an unrelenting weight upon their shoulders.

"We're all tough and mean," he says. "But if you don't learn how to deal with the things you saw in the library, it will eat you up.

"Right now, I just want it to be finished. Then I'll think about the impact on me."

The final report of the investigation task force will be made public in the next few weeks and forwarded to Gov. Bill Owens' Columbine Commission. That panel will review the investigation and the response to the disaster at Columbine.

But the criminal case will be left open indefinitely. There is no statute of limitations on murder.

Investigators had hoped to keep sealed some of the most gruesome and shocking evidence, including crime scene photographs and the Harris-Klebold videotapes.

Leaving the case open, investigators had hoped, also would allow investigators to keep sealed some of the most gruesome and shocking evidence, including crime scene photographs and the Harris-Klebold videotapes.

Their reasoning was simple.

First, they wanted to protect the integrity of the evidence in the event anyone comes forward with new information.

Second, they didn't want to do anything to hurt the families of those injured and killed at Columbine -- families the investigators had come to know well and care about.

But now the Sheriff's Department has made the videotapes public, and it's unclear what impact that will have on the disclosure of remaining evidence.

No matter how exhaustive, the official report will never tell the entire story or measure the deep scars this tragedy left on the victims and the community.

It won't say that Coroner Nancy Bodelson still struggles to retain her composure when she thinks about the kids on the floor of the Columbine library.

Or that John Kiekbusch, commander of the investigation, worries that the community may yet face the same phenomenon that played out after the Oklahoma City bombing: suicides among police officers, paramedics and firefighters who rushed to the scene.

Or record the chill investigators still feel when they consider that the cafeteria bombs could have killed hundreds of children.

Or show the look on District Attorney Dave Thomas' face when he recalls the eyes of a broken-hearted father, just informed his son was dead.

Or explain why Sgt. Rich Webb and others wonder when -- not if -- someone will try to outdo Harris and Klebold.

Or finally answer the one question that remains on everyone's lips:


"I think I know why they did it," the FBI's Fuselier says. "It was because they were so filled with hate.

"But the real question is why they had so much hate inside them."