The gunman who killed 32 people at Virginia Tech university mailed a package of photographs, videos and writings to NBC News before he died.

In a profane, sometimes incoherent videotaped rant, the gunman expressed rage and resentment. He showed off his guns, and in a lengthy written manifesto, railed against the world.

He also recalled the school killings at Columbine High School in Colorado in 1999.

NBC said a time stamp contained in the package indicates it was sent in the middle of the Monday morning rampage at the university in Blacksburg, Va. It was likely mailed after the gunman killed two students in a dormitory, but before he opened fire in an engineering and science building two hours later.

The gunman killed 30 people in the second building, then shot himself.

Police have identified the gunman as Cho Seung-Hui, a 23-year-old undergrad enrolled in his senior year as an English major, police say.

A native of South Korea, Cho moved to the United States at age eight and grew up in the Washington, D.C., suburb of Centreville, according to U.S. immigration records.

NBC News received the package, which was addressed with an incorrect zip code, at its New York City office on Wednesday morning, according to MSNBC's website. NBC staff wore gloves when they handled it and passed it on to the FBI in New York immediately.

No clear motive for killings

Police said it's not yet clear what motivated the rampage.

Police did have contact with Cho as far back as the fall of 2005, according to police records.

In November 2005, a female student called police and said she was receiving unwanted phone calls from Cho. Police referred Cho to the office of judicial affairs, but the female student declined to press charges against him.

In December 2005, another female student reported she felt Cho was stalking her and sending her e-mails. She told police but also opted not to lay charges.

Officers followed up the next morning and spoke with Cho. The next morning, an "acquaintance" of Cho called police to say Cho was suicidal as a result of the investigations, said police Chief Wendell Flinchum.

Police took Cho to a mental health counsellor, who determined he should be referred to mental health officers for evaluation. Due to privacy laws, details about the temporary detention order are confidential.

Also in December 2005, Cho's writing teacher contacted authorities to share concerns about violent imagery in Cho's creative writing assignments, but no official report was filed.

For more than a year afterward, police did not hear another report of any other trouble from the student, Flinchum said.

With files from the Associated Press