so disturbing

sick to my stomach.

BLACKSBURG, Va. - Between his first and second bursts of gunfire, the Virginia Tech gunman mailed a package to NBC News containing what authorities said were video, photos of himself brandishng weapons, and a rambling diatribe about getting even with rich people.

"This may be a very new, critical component of this investigation. We're in the process right now of attempting to analyze and evaluate its worth," said Col. Steve Flaherty, superintendent of Virginia State Police. He gave no details on the material.

NBC said that a time stamp on the package indicated the material was mailed in the two-hour window between the first burst of gunfire in a high-rise dormitory and the second fusillade, at a classroom building.

The package included digital images of him holding weapons and a manifesto that "rants against rich people and warns that he wants to get even," according to a law enforcement official who spoke on the condition of anonymity because he was not authorized to speak about the case.

NBC said it immediately turned the package over to authorities on Wednesday. NBC would not disclose the contents beyond characterizing the material as "disturbing." The package was sent to NBC News head Steve Capus.

If the package was indeed mailed between the first attack and the second, that would help explain where Cho was and what he did during that two-hour window