As the country prepares to mark 10 years since the massacre at Columbine High School in Colorado, many of the "facts" about the school shooting turn out to be myth, USA Today reports.

On April 20, 1999, teenagers Eric Harris and Dylan Klebold killed 13 at the school and injured 24 others before killing themselves in what at the time was the country's worst school shooting.

Now details have emerged to suggest that Harris and Klebold were not the "Trenchcoat Mafia," were not loners warped by video games and weren't even bullied by classmates, according to USA Today's report on new studies of the massacre. In fact, the young men reportedly bragged in their journals about picking on other students.

Books analyzing the shooting through diaries, e-mails, calendars, videos, police affidavits and interviews find that many misconceptions need to be debunked.

For example, the gunmen did not target anyone and never fatally shot a student in the head who professed her faith in God, as was widely reported. The newspaper notes that new evidence indicates the teens wanted to kill several thousand people – including their friends.

The pair also reportedly had prepared the attack for more than a year, and they built more than 100 bombs and collected guns from friends. Their suicidal plan was to conclude with a pair of gasoline bombs set to kill emergency responders, parents and journalists, but the poorly made bombs never went off.

Click here to read the full USA Today report.