Gunman at University of Texas Austin Identified as Sophomore Math Major Colton Tooley

Sept. 28, 2010— -- A 19-year-old math major got dressed in a suit and a ski mask and fired off several rounds from an AK-47 assault rifle today, sending the campus of the University of Texas at Austin into a lockdown before taking his own life in a library, police said.

Colton Tooley was seen running through the campus this morning as classes started. He was wearing a dark business suit, carrying a rifle and shooting rounds into the air.

Police told ABCNews.com that the investigation had moved off campus to a "house associated with the shooting."

Tooley was a sophomore math major at UT, concentrating in actuarial sciences, according to the student directory. Public records indicate that Tooley lived in South Austin, about 10 miles away from the university. Calls made to a number at that address went unaswered, but recorded answering machine message identified Tooley as a resident.

Just before noon, a campus lockdown that had been in effect since around 8 a.m., was lifted, and police ended a search for a possible second suspect.

"The armed suspect is dead. No other injuries have been reported," UT President Bill Powers wrote in a campus email.

Tooley was found dead on the sixth floor of the library from apparently self inflicted wounds, police said.

An email and text alert was sent to students and faculty around 8 a.m., just as the day's first classes were beginning, warning that an "armed subject was reported last seen at Perry Castaneda Library" and telling students to remain in place.

"I was walking to class, a little late," senior Robby Reeb told ABCNews.com. "I was walking from the business school, and a guy sprinted past me screaming, 'There's a guy with a gun.' I looked up and saw a man in a ski mask, wearing a suit, and carrying an assault rifle. And I called 911."

Reeb said he was outside between two buildings and had to choose which one to enter to avoid the shooter.

Students reported hearing bursts of gunfire. Police confirmed Tooley was carrying an AK-47, a military-grade combat rifle. Authorities said there were currently two crimes scenes: the library where the gunman was found dead, and an area outside where he fired shots into the air.

At a press conference police said they had not yet determined a motive.

Texas University Campus Was Locked Down After Shooting

Buildings near the library were placed on immediate lockdown, while some classes on the opposite side of campus were dismissed, said Miriam Smith, 22, a senior at the school.

"I had an 8 a.m. class this morning and a student checked Twitter and said that there's a shooter on campus," Smith said.

The area around the library was sealed off with yellow police tape. Heavily armed SWAT vehicles and officers carrying automatic weapons patroled the campus and bomb sniffing dogs were brought in to determine if explosives were left behind, police said.

Police said they initially received reports of gunmen fitting two different descriptions. They said they would work all leads and clear every building to determine there was no second shoot.

"We're conducting building searches. We need to clear every building in the immediate area. You can imagine that's going to take a little while," Police Chief Art Acevdo told radio station Mix 94.7. "We still are looking for a second suspect, hopefully we'll be able to get, if he even exists."

Once police confirmed Tooley had taken his own life, students were still cautioned stay in place and not return to campus: "If you are off campus, STAY AWAY. If you are on campus, lock doors, do not leave your building."

The university was the site of one of America's most infamous campus shootings when Charles Joseph Whitman, a student and former Marine, killed 14 people and injured 32 others in 1966. Whitman climbed 29 floors to the observation deck of the school's iconic tower and began picking people off with a rifle. He was eventually shot by police. That was the second deadliest school shooting in the United States behind the massacre at Virginia Tech in 2007.