Then I read this post from a crime scene investigator who worked the Columbine shooting. The post seems to have been taken down now. Maybe it was too sensitive, even years later, to talk about that day.
But he said:
"One of the only criticisms from processing Columbine was that we left the victim's bodies in the school overnight. It wasn't an easy decision I can assure you. But we believed strongly that the case would eventually go to court (either civil or criminal) despite the fact that the killers were deceased. Truthfully, you can't afford to think otherwise. So it's not as simple as just walking in a putting the victims in body bags. We can't levitate them out of the scene. People have to walk in there to get them and those people could possibly damage or destroy evidence if they aren't careful. The bodies have to be carefully photographed, videotaped, and measured with precision. The CSIs may have to collect trace evidence from their bodies or clothing. Adjacent objects that may be disturbed also have to be fully documented before a path can be cleared. You can't just kick a piece of evidence out of the way. So all of this process takes time. We don't like it either but we have to do everything we can to make sure the evidence can be presented in court."