This video frame grab image taken from a video aired by AP Photo/NBC   Blacksburg, Va., customers watch "NBC Nightly News" as they dine in a local restaurant today. Between his first and second bursts of gunfire, Virginia Tech gunman Cho Seung-Hui mailed a package to NBC that contained photos of him brandishing guns and video of him delivering an angry, profanity-laced tirade. AMY SANCETTA | Associated Press

"You had a hundred billion chances and ways to avoid today," 23-year-old Cho Seung-Hui said in an excerpt shown on "NBC Nightly News." He added: "The decision was yours. Now you have blood on your hands that will never wash off."

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. Thirty-three people died in the rampage, including the gunman, who committed suicide.

"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, which NBC said it received in Wednesday morning's mail.

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

MSNBC said the package included a CD-ROM on which Cho read his manifesto.

SOME MATERIAL TO AIR ON NEWS TONIGHT

Late Wednesday, MSNBC showed a photo from the package of Cho glaring at the camera, his arms outstretched with a gun in each hand. He wears a khaki-colored military-style vest, fingerless gloves and a backwards, black baseball cap. "NBC Nightly News" planned to show some of the material Wednesday night. The show airs at 5:30 p.m. Hawai'i time.

NBC News President Steve Capus said the network promptly turned the material over to the FBI in New York.

The material is "hard-to-follow ... disturbing, very disturbing very angry, profanity-laced," he said on the MSNBC Web site. Among the materials are digital video files showing Cho talking directly to the camera about his hatred of the wealthy, Capus said.

It does not include any images of the shootings Monday, but contains "vague references," including "things like, 'This didn't have to happen,"' Capus said.

The package bore a Postal Service stamp showing that it had been received at a Virginia post office at 9:01 a.m. Monday, about an hour and 45 minutes after Cho first opened fire, according to MSNBC.

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.

WARNING SIGNS INCLUDED STALKING INCIDENTS

Earlier in the day Wednesday, authorities disclosed that more than a year before the massacre, Cho was accused of stalking two women and was taken to a psychiatric hospital on a magistrate's orders because of fears he might be suicidal. He was later released with orders to undergo outpatient treatment.

The disclosure added to the rapidly growing list of warning signs that appeared well before the student opened fire. Among other things, Cho's twisted, violence-filled writings and sullen, vacant-eyed demeanor had disturbed professors and students so much that he was removed from one English class and was repeatedly urged to get counseling.

In November and December 2005, two women complained to campus police that they had received calls and computer messages from Cho, but they considered the messages "annoying," not threatening, and neither pressed charges, Virginia Tech Police Chief Wendell Flinchum said.

Neither woman was among the victims in the massacre, police said.

Around the same time, one of Cho's professors informally shared some concerns about the young man's writings, but no official report was filed, Flinchum said.

After the second stalking complaint, the university obtained a temporary detention order and took Cho away because an acquaintance reported he might be suicidal, authorities said. Police did not identify the acquaintance.

COURT PAPERS INDICATE MENTAL ILLNESS

On Dec. 13, 2005, a magistrate ordered Cho to undergo an evaluation at Carilion St. Albans, a private psychiatric hospital. The magistrate signed the order after an initial evaluation found probable cause that Cho was a danger to himself or others as a result of mental illness.

The next day, according to court records, doctors at Carilion conducted further examination and a special justice, Paul M. Barnett, approved outpatient treatment.

A medical examination conducted Dec. 14 found that that Cho's "affect is flat. ... He denies suicidal ideations. He does not acknowledge symptoms of a thought disorder. His insight and judgment are normal."

The court papers indicate that Barnett checked a form that Cho "presents an imminent danger to himself as a result of mental illness." Barnett did not check the box that would indicate a danger to others. He ordered Cho to comply with all recommended treatments on an outpatient basis.

It is unclear how long Cho stayed at Carilion, though court papers indicate he was free to leave as of Dec. 14. Virginia Tech spokesman Larry Hincker said Cho had been continually enrolled at Tech and never took a leave of absence.

A spokesman for Carilion St. Albans would not comment.

AVOIDING BLAME ON ANY ONE PERSON

Though the stalking incidents did not result in criminal charges, police referred Cho to the university's disciplinary system, Flinchum said. But Ed Spencer, assistant vice president of student affairs, would not comment on any disciplinary proceedings, saying federal law protects students' medical privacy even after death.

Some parents complained that more had not been done after the first shootings. Still, two days after the shooting spree, many students resisted pointing fingers.

"Who would've woken up in the morning and said, 'Maybe this student who's just troubled is really going to do something this horrific?"' said Elizabeth Hart, a communications major and a spokeswoman for the student government.

Jen Meadows, the student president of Sexual Assault and Dating Violence Education by Students, said at first she was "very, very mad at the administration."

But the more she learned about Cho, the more convinced she became that there was no way the killings could have been prevented. "People who are this mentally ill, there's not much more anyone could do with someone who's going to snap," she said.

Police searched Cho's dorm room and recovered, among other items, two computers, books, notebooks, a digital camera, and a chain and combination lock, according to documents. The front doors of Norris Hall, the classroom building where Cho and 30 of his victims died, had been chained shut from the inside during the rampage.

Fourteen people remained hospitalized Wednesday.

Lucinda Roy, professor of English at Virginia Tech, said that she, too, relayed her concerns to campus police and various other college units after Cho displayed antisocial behavior in her class and handed in disturbing writing assignments.

But she said authorities "hit a wall" in terms of what they could do "with a student on campus unless he'd made a very overt threat to himself or others." Cho resisted her repeated suggestion that he undergo counseling, Roy said.

POET ONE OF FIRST TO RECOGNIZE PROBLEMS

One of the first Virginia Tech officials to recognize Cho's problems was award-winning poet Nikki Giovanni, who kicked him out of her introduction to creative writing class in late 2005.

Students in Giovanni's class had told their professor that Cho was taking photographs of their legs and knees under the desks with his cell phone. Female students refused to come to class. She said she considered him "mean" and "a bully."

Questions lingered over whether campus police should have issued an immediate campus-wide warning of a killer on the loose and locked down the campus after the first burst of gunfire.

Police said that after the first shooting, in which two students were killed, they believed that it was a domestic dispute, and that the gunman had fled the campus. Police went looking for a young man, Karl David Thornhill, who had once shot guns at a firing range with the roommate of one of the victims. But police said Thornhill is no longer under suspicion.

Colleges and universities are considering a host of new security measures in the aftermath of the massacre, including outdoor warning systems, text message alerts and cameras that detect suspicious activity.

"Would a blast e-mail have been the most effective tool in notifying people of Monday's events?" asked John Holden, a spokesman for DePaul University in Chicago. "Some of the coverage I'm seeing suggests that old-fashioned emergency alarms or broadcast announcements would probably have been more effective."