An advance copy of the Columbine Review Commission report said all reports of verbal and written threats should be taken seriously.
"An inquiry into sensitive topics like these can be difficult, but all of them may well have to be considered and evaluated if the members of a team are to understand the extent to which a student's threatening conduct or statements should be taken seriously," the report said.
The Governor's Columbine Review Commission, formed shortly after the April 20, 1999, shootings, compiled the report - some 200 pages - long on the attack that left 15 dead, including gunmen Eric Harris and Dylan Klebold, and about two dozen more wounded.
A commission official said this week the report would offer recommendations on ho to prevent, or better respond to, a similar school shooting. The report also includes a detailed chronology on Columbine, and the events leading up to it.
The commission heard expert testimony while reviewing the shootings but did not have subpoena power and was unable to order Jefferson County Sheriff John Stone to testify. Stone oversaw the emergency response to Columbine.
The sheriff refused to appear before the review commission because of lawsuits, but Columbine principal Frank DeAngelis testified that no warning signs were ignored by teachers.
"They had no prior knowledge that Eric and Dylan could have carried out what they did that day," DeAngelis said, dismissing charges that the gunmen had been bullied.
The father of a slain student said he doesn't expect the report to reveal anything new. Brian Rohrbough, whose 15-year-old son, Daniel, was shot outside the school, said he wants the commission to urge the governor to empanel a state grand jury.
"The commission was set up under a bad premise, which was not to point fingers," Rohrbough said.
Victims' families have filed nine lawsuits claiming the sheriff's office botched the response to the attack and didn't follow through on reports beforehand that Harris made threats over the Internet and was making pipe bombs.
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