Cho Seung-Hui, the gunman in the Virginia Tech shootings, mailed a package to NBC News before he entered Norris Hall, a source tells our brother TVNewser. Developing ...

UPDATE #1:

Alex Witt on MSNBC at 4:23PM: "NBC News has become to some degree a part of this investigation ... NBC News has received some information from the deceased shooter ... In which we received a package that included some images a lengthy diatribe. We believe it may shed some light on what he was doing between the first shooting and the second ... It includes some images, disturbing, rambling, multi-page statement ... NBC News immediately turned this information over to authorities to assist in their investigation ... We are not going to give out any specifics of the information ..."

UPDATE #2:

Blacksburg authorities: "The correspondence included multiple photos, video and writings ... I certainly want to commend NBC News for what they've done, the way they've secured this information, and the way they handled it with dignity ... The originals were turned over to the FBI ... This may be a very new, critical component of this investigation ... we are in the process right now of analyzing and evaluating its work."

UPDATE #3:

NBC News statement: "NBC received a communication from Cho Seung-Hui, the man identified by police as the Virginia Tech shooter, via the US Mail this morning and immediately turned it over to the authorities. The package included images, videos and writings, and appears to have been mailed between the two shootings. We are cooperating fully with the authorities."