For investigators, the big bombs changed everything: the scale, the method, and the motive of the attack. Above all, it had been indiscriminate. Everyone was supposed to die. Columbine was fundamentally different from the other school shootings. It had not really been intended as a shooting at all. Primarily, it had been a bombing that failed.
That same day, officials announced the discovery of the big bombs, and their destructive power. It instigated a new media shock wave. But, curiously, journalists failed to grasp the implications. Detectives let go of the targeting theory immediately. It had been sketchy to begin with, and now it was completely disproved. The media never shook it off. They saw what happened at Columbine as a shooting and the killers as outcasts targeting jocks. They filtered every new development through that lens.
Obviously, and thankfully, the large bombs that the instigators had set failed on the day.I was really surprised to read that Columbine was intended primarily as a bombing inspired by Timothy McViegh, not as a school shooting motivated by the bullying, revenge etc as assumed by nearly everyone.