http://story.news.yahoo.com/news?tmpl=story&cid=514&e=2&u=/ap/20040226/ap_on_re_us/columbine_investigation<Snip>
Ken Salazar also said he is investigating whether authorities tried to cover up what they knew about the rampage. However, he did not blame the Jefferson County sheriff's office for missing warning signs about Eric Harris and Dylan Klebold, and said he found no evidence of negligence.
But the attorney general said his investigation is not complete and has grown since he was asked to look into contacts between the killers and investigators beginning in 1997, two years before the attack.
Salazar said his staff interviewed two former sheriff's officials just this week. He also said authorities are still trying to find a file detailing a search warrant affidavit for Harris' home after a pipe bomb was found along a bike path in 1998 — a search that never took place.
"We are still looking for that file," Salazar said.