An investigative report found university authorities waited 2 hours before sending out a campus-wide e-mail alerting students a gunman was loose even while some of those officials locked down their own offices or contacted loved ones saying they were all right, The Washington Post reported.
The report affirms a preliminary finding released in the spring, the newspaper said Thursday.
"While Virginia Tech failed to adequately warn students that day, we recognize that the university has put far-reaching changes in place since that time to help improve campus safety and better protect its students and community," Education Secretary Arne Duncan said.
Federal investigators said Virginia Tech violated the Clery Act requiring universities to send out timely warnings of imminent threats.
Had they done so, Cho might not have had the opportunity to fatally shoot 32 people, the report said.
Virginia Tech authorities discovered two fatally shot bodies in a dorm room at 7:30 a.m. April 16, 2007, but waited until 9:26 a.m. to issue a campus-wide e-mail saying only "a shooting incident occurred" -- not that two students were dead, the Post reported.
School officials say they had no way to predict the campus was about to be the scene of a massacre based on the discovery of only two bodies.