Virginia Tech violated federal law by waiting too long to notify students during the 2007 shooting rampage, according to a final report from the U.S. Department of Education.
The department issued its report in January, but it gave Virginia Tech a chance to comment before drafting the final version, which was issued Thursday.
The report finds that the university failed to issue a timely warning after the gunman killed two students in a dormitory early on April 17, 2007.
The school sent out an e-mail about the shootings two hours later, but by that time the student gunman was chaining shut doors to a campus building, where he killed 30 students and faculty before turning the gun on himself.
A university spokesman disputed the findings.
The Virginia Tech shooting rampage is the deadliest peacetime shooting incident by a single gunman in U.S. history.