(CNN) -- On the morning of the 2007 shooting massacre that rocked the country, Virginia Tech officials had begun to lock down administrative buildings and some even warned their families nearly 90 minutes before the rest of campus was notified that a gunman was on the loose, a new report says.

Officials charged with sending the campus alert did not do so until 9:26 a.m. on April 16, 2007, according to the report, released by Virginia's governor Friday.

Police discovered the first shooting victims in a dormitory at 7:24 a.m., the report said. Some administrative buildings were subsequently locked down and by 8:05 a.m., at least two school staff members told family members about the dorm shootings, the report said.

Gov. Timothy Kaine issued the report as an addendum to the August 2007 panel report on the event.