Investigators and witnesses yesterday pieced together a South Korean student's path to mass murder on a US university campus, as details emerged of possible missteps in the early hunt for the killer.
Police had identified the gunman in Monday's killing of 32 students and staff at Virginia Tech university as Cho Seung-hui, 23, describing him as a student of English whose quiet behavior and death-filled writings worried his classmates.
Amid widespread anger among survivors and relatives over the university's failure to lock down campus when a gunman was on the loose, investigators revealed they may have initially been pursuing the wrong man, US media reported.
Police said that during a more than two-hour gap between a first shooting on Monday, in which a female and male student were killed, and the second in which 31 were killed, they were pursuing the boyfriend of the female victim, the New York Times reported.
The female victim's roommate "told the police that [Karl D.] Thornhill, a student at nearby Radford University, had guns at his town house," the newspaper said, quoting a police affidavit.
"The roommate told the police that she had recently been at a shooting range with Mr. Thornhill, the affidavit said, leading the police to believe he may have been the gunman," it said.
But as they questioned Thornhill, shooting was reported at the Norris Hall engineering building.
The delay meant Cho apparently had time to return to his room, take weapons and ammunition and head to the engineering building where he chained doors shut from the inside before shooting dead 30 people then turning his weapon on himself.
Police search warrants said a bomb threat note was found in the vicinity of Cho's body which it was "reasonable to believe" he had written. Cho was also carrying knives on him, and at least one more knife along with prescription medications for depression were found in his room.
Police recovered a 9mm handgun and a .22 caliber handgun from the crime scene.
Cho, who came to the US from South Korea in 1992 when he was eight years old, reportedly also left behind a rambling note venting his rage and complaining about "rich kids."
"You caused me to do this," he wrote in the several-page-long note that also railed against "debauchery" and "deceitful charlatans."
Cho had shown recent signs of "violent, aberrant behavior," including stalking women and setting a fire in a dorm room, the Chicago Tribune said.
South Korean students heading to the US yesterday expressed concern over a possible backlash after the Virginia massacre, but said they would not change their study plans.
South Korea has sent more students to study in the US than any other country, according to statistics from US Immigration and Customs Enforcement.
The number of South Korean students was 93,728 at the end of last year -- 14.9 percent of the total -- ahead of India at 76,708 and China at 60,850, according to a February report from the agency.
South Korean officials have expressed condolences as well as concern about a possible racial backlash that Koreans could face in the US after the Virginia tragedy.
High school senior Sim Yeong-eun, 18, said she would go to the US in August to study despite such concerns.
The attack "won't shake my decision as I've already made up my mind to go to the United States," Sim said.