By Siobhan Courtney
Interactive reporter, BBC News
YouTube removes video glorifying the Columbine school killers
YouTube has removed a number of videos glorifying the Columbine High School killers, after a BBC Six O'clock News investigation.
Videos found on the site praised Eric Harris and Dylan Klebold - also known as "Reb" and "Vodka" - for carrying out the shooting, in which 13 people died.
The killings near Denver, Colorado in 1999, were romanticised in the videos.
A YouTube spokesman said the volume of content submitted meant not all can be checked before reaching the site.
The Six O'clock News has discovered that nine years on from America's worst high school shooting there is a thriving online community obsessed with teenage gunmen Harris and Klebold.
Many tribute videos found on YouTube romanticise the killers who shot 12 pupils, a teacher and wounded 23 others before shooting themselves.
The BBC's investigation found it is not only American teenagers who are fascinated with the Columbine killers.
One 17-year-old video maker called Levi, from the North of England, said: "I made the video to raise awareness and I in no way shape or form meant it to look like that [a glorification of the killers].
"I wanted to show different sides of them, the personal sides of them, rather than glorifying it. I wanted to let people see behind the killers and see they were real people."
Twelve pupils and one teacher were killed, and 23 people injured
Levi's video was one which the BBC showed YouTube - a team of moderators then removed it because it breached the site's guidelines.
YouTube, which is owned by Google, said it was grateful to the BBC for bringing the videos to its attention.
Peter Barron, Head of Communication for Google UK, owners of the site said: "We do not tolerate videos that glorify school shootings and have removed the videos that fall into that category".
Mr Barron said it was impossible to pre-moderate the huge volume of material (13 hours every minute) which YouTube receives, and it relies on their users to flag up videos that need reviewing.
But Brian Rohrbough, whose 15-year-old son Danny died in the massacre, said he was worried about the effect such videos had on teenagers.
He said: "YouTube should maintain a certain degree of morality. A picture of my son lying dead in the sidewalk was used in a music video [not on YouTube] almost immediately after Columbine.
"This is the type of thing that our culture promotes."
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.