Apparently, it wasn't a simple "Trench Coat Mafia" versus the jocks . . .

Columbine was intended not primarily as a shooting at all, but as a bombing on a massive scale. If they hadn't been so bad at wiring the timers, the propane bombs they set in the cafeteria would have wiped out 600 people. After those bombs went off, they planned to gun down fleeing survivors. An explosive third act would follow, when their cars, packed with still more bombs, would rip through still more crowds, presumably of survivors, rescue workers, and reporters. The climax would be captured on live television. It wasn't just "fame" they were after—Agent Fuselier bristles at that trivializing term—they were gunning for devastating infamy on the historical scale of an Attila the Hun. Their vision was to create a nightmare so devastating and apocalyptic that the entire world would shudder at their power.

From slate.com