Cho Seung-Hui, the gunman who apparently killed 32 people and himself Monday morning at Virginia Polytechnic Institute and State University in Blacksburg, Va., seems to have been a shy, quiet type seething with rage at unspecified tormentors.
Virginia Tech police on Tuesday morning identified Cho, 23, as the man whose body had been found in Norris Hall, site of the worst shooting spree in American history, lying next to two semi-automatic pistols.
He apparently had scrawled the words "ISMAIL AX" on the inside of one arm, according to the Chicago Tribune, which may be a reference to the Islamic account of the Biblical sacrifice of Abraham.
A rambling note left in Cho's dorm room reportedly railed for several pages against "rich kids" and "debauchery" and "deceitful charlatans" on campus, and at one point states, "You caused me to do this."
An English professor said Cho's creative-writing work was so disturbing that he had been referred to on-campus counseling services.
In one class, he refused to speak and signed his name using a question mark. Fellow pupils called him "The Question Mark Kid."
There were also reports that Cho, a senior majoring in English from Centreville, Va., had been taking medication for depression, and had also recently set fire to a dorm room and stalked women.
Identification was delayed nearly 24 hours after the end of the rampage because Cho was carrying no ID, had no police record and had severely damaged his own face when he killed himself.
A positive match was finally made with fingerprints on immigration records.
"He was a loner, and we're having difficulty finding information about him," Virginia Tech spokesman Larry Hincker said Tuesday morning.
Cho was born in South Korea on Jan. 18, 1984 and entered the United States in 1992 as a child of 8. He was a permanent resident alien, a "green card" holder entitled to most of the legal rights held by U.S. citizens.
The Last Hours
Cho's last hours apparently began with the killings of freshman veterinary student Emily Hilscher, 19, and senior Ryan "Stack" Clark, a resident advisor, at about 7:15 a.m. in the West Ambler Johnston residence hall.
Hilscher's connection to Cho is not clear. The police who responded to 911 calls described the incident as a "domestic dispute," implying that she and the gunman had some sort of relationship, but at least one report said they did not know each other.
"As far as we can tell, wrong place, wrong time," said John W. McCarthy, an administrator for rural Rappahannock County, Va., where Hilscher's family lives, to the Washington Post. "She was a beautiful, smart, great kid."
What seems clear is that Clark, as the most immediate authority, tried to intervene and was killed for his trouble.
Police on Tuesday said one of the guns found with Cho's body had been used to shoot Hilscher and Clark, though he had not been firmly established as their killer.
"It's certainly reasonable to assume that Cho was the shooter in both cases," said Col. Steve Flaherty, superintendent of the Virginia State Police.
Cho was gone by the time police arrived at West Ambler Johnston. Officers told the nearly 900 resident students to stay in their rooms, began questioning a mutual acquaintance of Hilscher and Clark and considered the incident essentially over.
The New York Times reported Wednesday that police may have been misled by a false lead. According to the paper's sources, Hilscher's roommate told officers Hilscher's boyfriend attended nearby Radford College, and had several guns; he was being questioned when the reports of more shootings at Norris Hall came in.
In the meantime, Cho had apparently returned to his own dorm room in Harper Hall to re-arm himself and to write a note before heading across campus to Norris Hall, which houses the bulk of Virginia Tech's famed engineering courses.
He was carrying a 9-millimeter Glock 19 semi-automatic pistol, which he had legally bought five weeks earlier at a gun shop in nearby Roanoke, as well as a 22-caliber Walther P22 semi-automatic pistol and several clips of ammunition.
Two law enforcement officials, speaking on condition of anonymity because the information had not been announced, said Cho's fingerprints were found on the guns used in both shootings. The serial numbers on the two weapons had been filed off, the officials said.
A Better Life
Cho's hometown of Centreville, Va., lies in an affluent part of Fairfax County, about 30 miles west of Washington, D.C. and is near Washington Dulles International Airport and the Manassas Civil War battlefields.
Cho's parents live in an off-white two-story townhouse on a residential street, and reportedly own a dry-cleaning business. Police visited the house Monday night.
South Korea's largest newspaper, Chosun Ilbo, reported Wednesday that Cho's family was poor when they lived in a Seoul suburb and had decided to emigrate to seek a better life.
The family lived in a rented, basement apartment — usually the cheapest unit in a multi-apartment building, the newspaper reported quoting building owner Lim Bong-ae, 67. Police identified the shooter's father as Cho Seong-tae, 61.
"I didn't know what [Cho's father] did for a living. But they lived a poor life," Lim told the newspaper. "While emigrating, [Cho's father] said they were going to America because it is difficult to live here and that it's better to live in a place where he is unknown."
Cho himself attended Fairfax County public schools, graduating from Westfield High School in Chantilly in 2003.
He had a sister who attended Princeton. The Washington Post said she graduated in 2004 and now works as a contractor for the State Department.
A photo from the 2002 yearbook, when Cho was a junior, shows an unsmiling, bespectacled boy wearing a plaid flannel shirt over a light-colored T-shirt. He did not have a yearbook photo his senior year, which may simply mean he failed to show up for the photographing.
At least one of those killed in the rampage, Reema Samaha, graduated from Westfield High in 2006. But there was no immediate word from authorities on whether Cho knew the young woman and singled her out.
Neighbor Abdul Shash said the gunman played basketball and wouldn't respond if someone greeted him.
He was "very quiet, always by himself," said Shash.
The 'Question Mark Kid'
Those tendencies carried on into college, where Cho apparently made it through nearly four years without making many friends.
Classmates said that on the first day of an introduction to British literature class in the fall of 2005, the 30 or so English students went around and introduced themselves.
When it was Cho's turn, he didn't speak.
The professor looked at the sign-in sheet and, where everyone else had written their names, Cho had written a question mark.
"Is your name, 'Question mark?'" classmate Julie Poole recalled the professor asking.
The young man offered little response.
Cho spent much of that class sitting in the back of the room, wearing a hat and seldom participating. In a small department, Cho distinguished himself for being anonymous.
"He didn't reach out to anyone. He never talked," Poole said. "We just really knew him as the 'question mark kid.'"
Even his roommate, Joseph Aust, said he and Cho rarely conversed.
"I tried to make conversation with him earlier in the year when he moved in," Aust told ABC's "Good Morning America." "He would just give one-word answers and stay quiet. He pretty much never looked me in the eye."
'He Could Be a School Shooter'
A Virginia Tech professor said Cho's work in creative-writing class was so disturbing that he had been referred to the school's counseling service.
Professor Carolyn Rude, chairwoman of the university's English department, said she did not personally know the gunman.
But she said she spoke with Lucinda Roy, the department's director of creative writing, who had Cho in one of her classes and described him as "troubled."
"There was some concern about him," Rude said. "Sometimes, in creative writing, people reveal things and you never know if it's creative or if they're describing things, if they're imagining things or just how real it might be. But we're all alert to not ignore things like this."
She said Cho was referred to the counseling service, but she said she did not know when, or what the outcome was. Rude refused to release any of his writings or his grades, citing privacy laws.
Professor Roy told the New York Times she tutored Cho individually in the fall of 2005 after his writings and behavior had intimidated his classmates.
During the sessions, she said, he wore sunglasses and a baseball cap pulled low on his forehead.
"He seemed to be crying behind his sunglasses," Roy told the newspaper.
She also said she had been so worried about tutoring Cho that she developed a plan with her assistant — if she mentioned the name of a dead professor, the assistant would know to call campus security.
The Web site The Smoking Gun on Tuesday posted a play Cho allegedly wrote last year. Entitled "Richard McBeef," the violent, possibly darkly comic one-act play concerns an argument between the title character and his 13-year-old stepson, who accuses him of murdering his father and of pedophilia.
The play seems sympathetic to the stepfather, who tries to defend himself in vain against his wife and stepson's accusations. It ends on an ambiguous note, with the stepfather swinging a "deadly blow" at the boy.
"When we read Cho's plays, it was like something out of a nightmare," former classmate Ian MacFarlane, now an AOL employee, wrote in a blog posted on an AOL Web site.
"The plays had really twisted, macabre violence that used weapons I wouldn't have even thought of."
He said he and other students "were talking to each other with serious worry about whether he could be a school shooter."
Poet Nikki Giovanni, one of his professors, told a cable news channel Wednesday that her students were so unnerved by Cho's behavior that she had security check on her room and eventually had him taken out of her class.
Some students had stopped coming to class, saying Cho was taking photos of them with his cell phone, she said.
Giovanni told the Washington Post that after one instance when Cho recited his poetry in class, seven out of 70 students showed up for the next meeting.
She asked about the absences, and was told the other students were afraid of Cho.
"It was not bad poetry. It was intimidating," Giovanni said of his writing. "At first I thought, OK, he's trying to see what the parameters are. Kids curse and talk about a lot of different things. He stayed in that spot. I said, 'You can't do that.' He said, 'Yes, I can.' I said, 'No, not in my class.'"
"We always joked we were just waiting for him to do something, waiting to hear about something he did," said another classmate, Stephanie Derry. "But when I got the call it was Cho who had done this, I started crying, bawling."
A Virginia Tech police spokesman said Tuesday Cho had been issued a speeding ticket on April 7 for driving at 44 mph in a 25-mph zone on campus. His court date was set for May 23.
Cho has not been tied to two campus bomb threats in the past three weeks, but a note detailing a third bomb threat was found near the bodies in Norris Hall.
On Wednesday morning, yet another bomb threat had campus police evacuate Burrus Hall, another school building.
Sources told ABC News that an explanation for the mass murder may be found in the note from Cho's dorm room.
The note, which another law enforcement source described as typed and eight pages long, apparently begins in the present tense, then over the course of several pages switches to past tense, all the while lashing out at fellow students, according to ABC and the Chicago Tribune.
Sources also told the Tribune about the strange inscription on one of Cho's arms — the words "ISMAIL AX" in red ink.
The reference may be to the Biblical sacrifice of Abraham, in which God commands the patriarch to sacrifice his own son. Abraham begins to comply, but God intervenes at the last moment to save the boy.
In the Jewish and Christian traditions, the son is Isaac, father of the Jewish people; in Islam, it is his older half-brother, Ismail, or Ishmael in Hebrew.
Abraham uses a knife in most versions of the story, but some accounts have him wielding an ax.
A more obscure reference may be to a passage in the Koran referring to Abraham's destruction of pagan idols; in some accounts, he uses an ax to do so.
Cho's actions caused repercussions in the country of his birth. South Korean President Roh Moo-hyun on Tuesday delivered his condolences to the families of the Virginia Tech shooting victims, according to the Yonhap news agency.
Foreign ministry spokesman Cho Byung-se, no presumed relation, said the country was "in shock beyond description" and hoped that the incident would not "stir up racial prejudice or confrontation."
South Korea was the scene of one of the world's deadliest shooting sprees, when police officer Woo Beom-gon went from house to house on an eight-hour overnight rampage in 1982 in the southeastern village of Euiryeong, killing 55 people and wounding 35 others.
FOXNews.com's Melissa Drosjack, Paul Wagenseil and the Associated Press contributed to this report.