Joan Walsh initiated this project by publishing my early stories at Salon Salon. She gave me confidence and helped me find my voice. No writer could ask for more. David Plotz, David Talbot, Dan Brogan, Mim Udovich, and Toby Harshaw helped me continue reporting at other publications.

Early on, when I needed it, three veterans surprised me with e-mails of encouragement: Richard Goldstein, Frank Rich, and Jonathan Karp. You'll never know what that meant.

Jonathan first suggested the book. Mitch Hoffman later championed the project, guided early efforts, and helped me establish the tone. Jonathan returned for the crucial edit. I was struck by the clarity he brought. Jonathan gathered a wonderful team at Twelve and Hachette: his assistant, Colin Shepherd, added insightful notes on the manuscript; Karen Andrews did a thorough legal review; Bonnie Thompson redefined the term copyedit; copyedit; managing editor Harvey-Jane Kowal was patient with my changes; Henry Sene Yee, Anne Twomey, and Flag Tonuz provided a great design. Cary Goldstein and Laura Lee Timko publicized the book well enough to get it into your hands. managing editor Harvey-Jane Kowal was patient with my changes; Henry Sene Yee, Anne Twomey, and Flag Tonuz provided a great design. Cary Goldstein and Laura Lee Timko publicized the book well enough to get it into your hands.

This book went through several incarnations. From first reporting to publication, it took ten years. The one person who never lost faith in it or me was my agent Betsy Lerner. She earned my deepest gratitude. She's also a great editor, advisor, shrink, and rock.

I built on the work of other great journalists, especially Dan Luzadder, Alan Prendergast, and Lynn Bartels. I owe them a great debt. Michael Paterniti reinspired me with his brilliant GQ GQ story on the tragedy. Wendy Murray generously shared her field notes. Mark Juergensmeyer's book gave me a deeper understanding of terrorists. Michelle Lopez and Mike Ditto were relentless researchers and fact-checkers. Dr. Frank Ochberg, Bruce Shapiro, Barb Monseu, and everyone at the Dart Center helped teach me about compassion for victims and for myself. story on the tragedy. Wendy Murray generously shared her field notes. Mark Juergensmeyer's book gave me a deeper understanding of terrorists. Michelle Lopez and Mike Ditto were relentless researchers and fact-checkers. Dr. Frank Ochberg, Bruce Shapiro, Barb Monseu, and everyone at the Dart Center helped teach me about compassion for victims and for myself.

I was stunned by the number of friends willing to volunteer their time and contribute so greatly to this book. David Yoo, Ira Gilbert, Joe Blitman, David Boxwell, Jeff Barnes, and Alan Becker provided great feedback as early readers. Alan stepped in countless times, like lending me his PC and babysitting my hard drive at Best Buy for hours on a Sunday night when it crashed just before a deadline. My mom typed and formatted the bibliography, and cheered every development. Thanks to the folks at Alexian and Health Futures for keeping me solvent with an intermittent day job and the flexibility to put the book first. Lydia Wells Sledge stands alone. She devoted a year of her life to serve as full-time unpaid reader, proofer, fact-checker, researcher, organizer, assistant, and tackler of every conceivable odd task. She claims to have enjoyed it.

Jeff Moores, Marilyn Saltzman, Rick Kaufman, Keith Abbot, and Bobbie Louise Hawkins helped in many ways. So many volunteers pitched in at my Web sites, especially Melisande, Greg Smith, and the moderators, tech staff, artists, and editors. Thanks to the writers and bloggers who featured my work, especially David Brooks, Hanna Rosin, Jeralyn Merritt, Duncan Black, Stephen Green, Scott Rosenberg, Will Leitch, Rolf Potts, Michelangelo Signorile, Cyn Shepard, and all the members of the Brokeback forum and Open Salon.

Ten years on a massacre can be tough on the soul. Great friends got me through. Extra thanks to Tito Negron, Gregg Trostel, Elizabeth Geoghegan, Staci Amend, Tom Kotsines, Jonathan Oldham, Patrick Brown, Jessica Yoo, Miles Harvey, Kevin Davis, Bill Kelly, Maureen Harrington, Andy Marusak, Tim Vigil, Karen Auvinen, Tom Willison, Pat Patton, Scott Kunce, Greg Dobbin, Ira Kleinberg, Justin Griffin, Chuck Roesel, Bill Lychack, Alex Morelos, the cabin group, Natalie and the Muckrakers in New Orleans, my eight siblings, seven nieces and nephews, and my parents, Matt and Joan Cullen. All the early readers deserve a repeat here, but especially David Yoo, for keeping me amused.

I've had thirty years of great teachers, ending with a string of insightful editors. I got there because of Reg Saner, Peter Michelson, Lucia Berlin, and my other profs at CU; Linda Tufano way back at The Daily Illini; The Daily Illini; and my high school journalism advisor, Mrs. Barrows. Mrs. Thacker, thanks for what you told me graduation day in 1979. I didn't forget. and my high school journalism advisor, Mrs. Barrows. Mrs. Thacker, thanks for what you told me graduation day in 1979. I didn't forget.

Those people helped me. I'm grateful to them and to everyone who helped the kids. Thanks to every paramedic, firefighter, cop, victim's advocate, teacher, custodian, shrink, Red Cross volunteer, detective, doctor, nurse, parent, sibling, friend, and anonymous stranger who came to the aid of the kids, the widow, and their families April 20 and afterward.

Notes.

This book relies heavily on the evidence compiled by investigators, including videos, photographs, and more than 25,000 pages of documents. Where the notes say a piece of evidence was released, it was my primary source, except as noted. Jeffco stamped most pages with a unique number in this format, JC-001-000009, where the 9 indicates it was the ninth page compiled. (The prefix "JC-001" is constant.) I provide the JC numbers and online links to most documents in the expanded Web version of these notes, at www.davecullen.com/columbine. Links to many other sources are also maintained there.

I also drew on my own reporting, and the work of other journalists. Three were exceptional: Dan Luzadder led a crack investigative team at the Rocky Mountain News Rocky Mountain News to reconstruct the events of April 20; Alan Prendergast of to reconstruct the events of April 20; Alan Prendergast of Westword Westword tirelessly and brilliantly pursued the questions of what police knew before the murders and the cover-up afterward; and Lynn Bartels of the tirelessly and brilliantly pursued the questions of what police knew before the murders and the cover-up afterward; and Lynn Bartels of the Rocky Mountain News Rocky Mountain News covered nearly every aspect of the story with an unrivaled thoroughness, thoughtfulness, and empathy. I built on their work and am profoundly grateful. Tom Kenworthy's flawless reporting for the covered nearly every aspect of the story with an unrivaled thoroughness, thoughtfulness, and empathy. I built on their work and am profoundly grateful. Tom Kenworthy's flawless reporting for the Washington Post Washington Post was also an early inspiration. was also an early inspiration.

Quotes from witnesses and survivors come from my reporting and reliable published accounts. All are attributed in the expanded online notes section. Significant outside sources are identified here.

Through their attorney, Sue and Tom Klebold verified much of the biographical information about their family and their activity after the attacks, adding small bits of information.

CHAPTER 1. MR. D.

He told them that he loved them: Most scenes involving Mr. D's speeches relied heavily on my interviews with him and were generally corroborated by others present. In many cases after the murders, I was present. I was the first journalist granted an in-depth interview with DeAngelis, which took place on July 4, 1999, in his office, for approximately two hours. I interviewed him more than twenty times over the next nine years. Most scenes involving Mr. D's speeches relied heavily on my interviews with him and were generally corroborated by others present. In many cases after the murders, I was present. I was the first journalist granted an in-depth interview with DeAngelis, which took place on July 4, 1999, in his office, for approximately two hours. I interviewed him more than twenty times over the next nine years.

twenty-four of Mr. D's kids: Twenty-four differs slightly from the figure in the introduction to the Twenty-four differs slightly from the figure in the introduction to the Sheriff's Office Final Report, Sheriff's Office Final Report, and from those in some other accounts. The number varies depending on whether those with relatively minor injuries are counted. Twenty-four students were listed, with the names of the hospitals providing treatment, on JC-001-011869 and JC-001-011870. The governor's commission also settled on twenty-four. Twenty-one were shot, and three injured trying to escape. and from those in some other accounts. The number varies depending on whether those with relatively minor injuries are counted. Twenty-four students were listed, with the names of the hospitals providing treatment, on JC-001-011869 and JC-001-011870. The governor's commission also settled on twenty-four. Twenty-one were shot, and three injured trying to escape.

CHAPTER 2. "REBELS".

pectus excavatum: Eric's medical records were released by Jeffco. He also discussed his reactions to the condition in several of his own writings. Eric's medical records were released by Jeffco. He also discussed his reactions to the condition in several of his own writings.

Dylan went by VoDKa: Capitalization varied. Eric posted it that way on his Web site. Sometimes Dylan wrote VoDkA, or just Vodka or V. Capitalization varied. Eric posted it that way on his Web site. Sometimes Dylan wrote VoDkA, or just Vodka or V.

Cold didn't deter the smokers: I made numerous trips to the smokers' pit over a nine-year period and found the students' behavior remarkably similar, with one exception: for several years after the shootings, students were suspicious of strangers and extremely hostile to the press. In time, that would change. I made numerous trips to the smokers' pit over a nine-year period and found the students' behavior remarkably similar, with one exception: for several years after the shootings, students were suspicious of strangers and extremely hostile to the press. In time, that would change.

a friend videotaped him: This scene came from video footage shot by a friend of the killers and released by police. They taped quite a bit of routine behavior. This scene came from video footage shot by a friend of the killers and released by police. They taped quite a bit of routine behavior.

CHAPTER 3. SPRINGTIME.

argued in the Washington Post: Washington Post: Schiraldi, "Hyping School Violence." Schiraldi, "Hyping School Violence."

A New York Times New York Times editorial editorial: Egan, "Where Rampages Begin."

CDC data: The 2008 CDC study "School-Associated Student Homicides: United States, 1992-2006" added the most recent data and corroborated the research Schiraldi cited. The 2008 CDC study "School-Associated Student Homicides: United States, 1992-2006" added the most recent data and corroborated the research Schiraldi cited.

CHAPTER 4. ROCK'N' BOWL.

Both boys asked for cash advances: The new owner, Chris Lau, described the advances the boys requested and received and Eric's promotion in his police interview. The new owner, Chris Lau, described the advances the boys requested and received and Eric's promotion in his police interview.

Eric had a phone engagement: Susan gave a detailed account of her interaction with Eric in her police interview.

CHAPTER 5. TWO COLUMBINES.

in the Columbine Lounge: Most descriptions of the Lounge and its clientele were my observations from several Friday and Saturday night trips, all after the murders. The anecdotes and individuals were all real, down to the song titles, and were representative. Additional details were filled in by Linda Sanders and by friends of Dave's who hung out there with him. These interviews were the primary basis for my accounts of Dave and Linda, before and after the tragedy. Most descriptions of the Lounge and its clientele were my observations from several Friday and Saturday night trips, all after the murders. The anecdotes and individuals were all real, down to the song titles, and were representative. Additional details were filled in by Linda Sanders and by friends of Dave's who hung out there with him. These interviews were the primary basis for my accounts of Dave and Linda, before and after the tragedy.

Dave Sanders taught typing: I am indebted to Marilyn Saltzman and Linda Lou Sanders for their book I am indebted to Marilyn Saltzman and Linda Lou Sanders for their book Dave Sanders: Columbine Teacher, Coach, Hero, Dave Sanders: Columbine Teacher, Coach, Hero, which I drew on heavily. I corroborated and/or fleshed out the elements I used with Linda and friends of Dave's. which I drew on heavily. I corroborated and/or fleshed out the elements I used with Linda and friends of Dave's.

"He was never home": This quote was based on Linda Sanders's recollection of the response by Dave's ex-wife. This quote was based on Linda Sanders's recollection of the response by Dave's ex-wife.

Cassie Bernall was not asked: Misty Bernall's memoir was extremely helpful in providing details about Cassie's life and about Brad and Misty's reactions to the tragedy. Additional information came from my interviews with Cassie's classmates, pastors, and church members, as well as TV interviews of the Bernalls. Journalist Wendy Murray also generously provided her field notes, including interviews with the Bernalls. Misty Bernall's memoir was extremely helpful in providing details about Cassie's life and about Brad and Misty's reactions to the tragedy. Additional information came from my interviews with Cassie's classmates, pastors, and church members, as well as TV interviews of the Bernalls. Journalist Wendy Murray also generously provided her field notes, including interviews with the Bernalls.

CHAPTER 6. HIS FUTURE.

Dylan was giddy: Descriptions of Dylan at home that afternoon came from people who watched the video Tom Klebold shot. Thanks to Wendy Murray for sharing her interview notes for some of them. Descriptions of Dylan at home that afternoon came from people who watched the video Tom Klebold shot. Thanks to Wendy Murray for sharing her interview notes for some of them.

CHAPTER 7. CHURCH ON FIRE.

This is a church on fire: The descriptions of all churches and services were from my observations. I attended worship services at nearly a dozen local churches but focused primarily on three: Trinity Christian Center, West Bowles Community Church, and the Foothills Bible Church. I attended services at each of those three more than a dozen times, all after the murders. The descriptions of all churches and services were from my observations. I attended worship services at nearly a dozen local churches but focused primarily on three: Trinity Christian Center, West Bowles Community Church, and the Foothills Bible Church. I attended services at each of those three more than a dozen times, all after the murders.

CHAPTER 8. MAXIMUM HUMAN DENSITY.

seven big bombs: It's possible there was an eighth. To avoid assisting copycats, Jeffco authorities will not specify certain details about the bombs. We know Eric produced two for the cafeteria, two for each car, and at least one decoy, using two tanks. The reports do not state whether that was a single device or two separate ones, and Kate Battan refused to say. It's possible there was an eighth. To avoid assisting copycats, Jeffco authorities will not specify certain details about the bombs. We know Eric produced two for the cafeteria, two for each car, and at least one decoy, using two tanks. The reports do not state whether that was a single device or two separate ones, and Kate Battan refused to say.

The main event was scripted: The killers' attack plan was reconstructed from a combination of their written and verbal descriptions, diagrams they made, and physical evidence, such as the placement of their cars (which they said would be used for initial firing positions). All those elements corroborated well. The killers' attack plan was reconstructed from a combination of their written and verbal descriptions, diagrams they made, and physical evidence, such as the placement of their cars (which they said would be used for initial firing positions). All those elements corroborated well.

he had nearly seven hundred rounds: Eric's journal chart for bomb production also included a section on ammo. He made a column for each gun, showing each acquisition and deducting for rounds spent in training. He did not label them, except for R (for Reb) beside one column and V (Vodka) next to another. Statements on the Basement Tapes a week and a half before the attack corroborate several entries and help identify what each column signifies. The chart tallies 143 rounds for Dylan's TEC-9, 129 for Eric's rifle, 295 for Dylan's shotgun, and 122 for Eric's (272 initially, less 150 fired off), for a total of 687. This was before Manes purchased the final hundred 9mm rounds, which could be split between the first two guns. Eric's journal chart for bomb production also included a section on ammo. He made a column for each gun, showing each acquisition and deducting for rounds spent in training. He did not label them, except for R (for Reb) beside one column and V (Vodka) next to another. Statements on the Basement Tapes a week and a half before the attack corroborate several entries and help identify what each column signifies. The chart tallies 143 rounds for Dylan's TEC-9, 129 for Eric's rifle, 295 for Dylan's shotgun, and 122 for Eric's (272 initially, less 150 fired off), for a total of 687. This was before Manes purchased the final hundred 9mm rounds, which could be split between the first two guns.

CHAPTER 9. DADS.

It came up unexpectedly: Dave's conversation with Mr. D in the bleachers was re-created based on my interviews with DeAngelis. Dave's conversation with Mr. D in the bleachers was re-created based on my interviews with DeAngelis.

team captain, Liz Carlston: The scene with Liz Carlston was based on her memoir. The scene with Liz Carlston was based on her memoir.

Linda Lou was asleep: The Monday and Tuesday scenes with Linda vary slightly from the depictions in the book she wrote with Saltzman. In my interview, Linda recalled a few things differently, and added more details. The Monday and Tuesday scenes with Linda vary slightly from the depictions in the book she wrote with Saltzman. In my interview, Linda recalled a few things differently, and added more details.

CHAPTER 10. JUDGMENT.

the boys rose early: The killers' activities on Tuesday morning were compiled from several sources: 1) eyewitness testimony of parents and neighbors who saw them coming or going, 2) time-stamped receipts, 3) video surveillance cameras at two stores where Eric bought gas and in the Columbine cafeteria, and 4) the killers' handwritten schedules for the morning and taped descriptions of their plans. Several schedules appeared in their notebooks and on assorted scraps of paper, with minor variations. The external evidence indicated that they stuck close to plan. The killers' activities on Tuesday morning were compiled from several sources: 1) eyewitness testimony of parents and neighbors who saw them coming or going, 2) time-stamped receipts, 3) video surveillance cameras at two stores where Eric bought gas and in the Columbine cafeteria, and 4) the killers' handwritten schedules for the morning and taped descriptions of their plans. Several schedules appeared in their notebooks and on assorted scraps of paper, with minor variations. The external evidence indicated that they stuck close to plan.

They got something to eat: Dylan's autopsy report indicted 160 cc of gastric contents, including "fragments of what appears to be potato skins." Given Dylan's love for fast food, that could have meant French fries. Eric's showed 250 cc, no specific contents. Dylan's autopsy report indicted 160 cc of gastric contents, including "fragments of what appears to be potato skins." Given Dylan's love for fast food, that could have meant French fries. Eric's showed 250 cc, no specific contents.

CHAPTER 11. FEMALE DOWN.

At 11:19 they opened: For depictions of the shootings, I relied mostly on police interviews with witnesses, the Jeffco For depictions of the shootings, I relied mostly on police interviews with witnesses, the Jeffco Sheriff's Office Final Report, Sheriff's Office Final Report, the governor's report, and the El Paso County sheriff's report. Discrepancies were sorted out through interviews with investigators, particularly lead investigator Kate Battan. I treated all Jeffco statements related to its own culpability and police response skeptically. However, the team's documentation of the killers' activities on April 20 was generally thorough and meticulous. Notable exceptions, such as information about Danny Rohrbough's killer, have been corrected. The El Paso County sheriff's department thoroughly reinvestigated Danny's shooting, reinterviewing about 130 witnesses and approaching 65 others who refused. Its 450-page report supersedes the Jeffco report on most of the outside gunfire. the governor's report, and the El Paso County sheriff's report. Discrepancies were sorted out through interviews with investigators, particularly lead investigator Kate Battan. I treated all Jeffco statements related to its own culpability and police response skeptically. However, the team's documentation of the killers' activities on April 20 was generally thorough and meticulous. Notable exceptions, such as information about Danny Rohrbough's killer, have been corrected. The El Paso County sheriff's department thoroughly reinvestigated Danny's shooting, reinterviewing about 130 witnesses and approaching 65 others who refused. Its 450-page report supersedes the Jeffco report on most of the outside gunfire.

Times came from the Sheriff's Office Final Report, Sheriff's Office Final Report, and were arrived at through a variety of means, including: witness testimony and time stamps on 911 calls, dispatch calls, and the surveillance video in the cafeteria. Patti Nielson's 911 call was particularly useful. She dropped the phone but left it off the hook, and 10 minutes, 48 seconds were recorded. The audio was then enhanced by the FBI crime lab. Every shot, crash, scream, and loud verbal exchange described by witnesses could be sequenced against a solid physical record. and were arrived at through a variety of means, including: witness testimony and time stamps on 911 calls, dispatch calls, and the surveillance video in the cafeteria. Patti Nielson's 911 call was particularly useful. She dropped the phone but left it off the hook, and 10 minutes, 48 seconds were recorded. The audio was then enhanced by the FBI crime lab. Every shot, crash, scream, and loud verbal exchange described by witnesses could be sequenced against a solid physical record.

Sean burst out laughing: Sean's perceptions of what was happening came from his police reports, conducted by both Jeffco and El Paso counties. Sean's perceptions of what was happening came from his police reports, conducted by both Jeffco and El Paso counties.

CHAPTER 12. THE PERIMETER.

The story took twenty-eight minutes: I relied on transcripts from ABC, CBS, NBC, CNN, and NPR for all descriptions and analysis of real-time TV and radio reporting. CNN stayed live for at least four hours. It had access to feeds from four local stations--affiliates of the three networks and one other station--and cut between them, providing a good cross section of local coverage as well. I relied on transcripts from ABC, CBS, NBC, CNN, and NPR for all descriptions and analysis of real-time TV and radio reporting. CNN stayed live for at least four hours. It had access to feeds from four local stations--affiliates of the three networks and one other station--and cut between them, providing a good cross section of local coverage as well.

CHAPTER 13. "1 BLEEDING TO DEATH".