4:30 p.m. Update: Investigators looking into the shooting on the University of Texas campus Tuesday are now said to be moving in and out of a house on the 3200 block of Western Drive in South Austin near William Cannon Drive and Brodie Lane, according to the Austin American Statesman who cited public documents that Colton Tooley lived in the home.
Earlier in the afternoon, Tooley was revealed as the gunman who stormed an library with an AK-47 and opened fire before turning the gun on himself.
The statesman reports that the street is a cul-de-sac and is blocked off by police and a crime scene vehicle. Additionally, the paper reports that Tooley is listed in the UT student directory as a sophomore math major with a focus on actuarial sciences with the College of Natural Sciences.
3 p.m. Update: Police have identified the man who opened fire on the University of Texas campus before killing himself as a 19-year-old Colton Tooley from Austin. Police said they believe Tooley acted alone.
College records indicate Tooley was a sophomore math major. His parents did not immediately respond to a message left by The Associated Press.
1 p.m. Update: Investigators now say there is no second suspect in Tuesday's shooting at the University of Texas at Austin where a gunman opened fire inside a library with an AK-47 before fatally shooting himself Tuesday morning, Austin police say.
The gunman is believed to be a student at the university, though officials said they are waiting on a medical examiner's identification of the person to be sure, according to KXAN-TV in Austin.
"University of Texas Police Department Chief Robert Dahlstrom said at 12:30 p.m. that their search for a potential second gunman or suspect turned up nothing - and that initial witness speculation that there may have been two threatening individuals appear to be false. He also said that multiple descriptions of the same person led to the belief of that second person," KXAN reported.
Noon Update: Police are still conducting an investigation and search to eliminate the possibility of a second suspect in connection with Tuesday's shooting.
Officials said the possibility of a second gunman was raised due to various descriptions of the gunman by witnesses.
"What we're doing right now is being methodical to eliminate a second suspect," said Austin Police Department Chief Art Acevedo.
A toll-free number has been set up for those seeking information: 866-657-9400.
At 12:05 p.m., UT placed the following message on their website after an "all clear" was issued:
Due to the events of today, the campus is closed. Unless you are needed for essential operations, all faculty, staff and students are urged to leave campus. Students who live on campus with the exception of Jester, San Jacinto, Prather, Roberts, Brackenridge and Moore Hill, may return to their residence halls.
What that means is that faculty and students are free to leave campus, but are not to go to the investigation area where the shooting took place.
Previous Updates: The incident took place inside the PCL library, one of the busiest undergraduate libraries on campus, when a man entered the building with an assault rifle just after 8 a.m. and opened fire on the sixth floor before fatally shooting himself, officials said.
Prior to entering the library, the gunman was reported to have been seen wearing a black ski mask, smiling and waving a gun near Dobie Mall; a high-rise dorm only a couple of blocks west from the library, according to a report in the Statesman.
Randall Wilhite, an adjunct law professor at the university, said he was driving to class when he saw "students start scrambling behind wastebaskets, trees and monuments," and then a young man carrying an assault rifle sprinting along the street. "He was running right in front of me ... and he shot what I thought were three more shots ... not at me. In my direction, but not at me, clearly not at me," Wilhite said. The professor said the gunman had the opportunity to shoot several students and Wilhite, but he did not.
Oscar Trevino told KXAN that his daughter, Martina, is a University of Texas employee and was on her way to work when she saw the gunman behind her as he fired a couple of shots. She began to run, tripped and sprained her ankle. Some people were able to help her inside a building and she is OK. "I just thank God she's fine," said Trevino.
Law enforcement from campus police, Austin police and the state Department of Public Safety rushed onto campus at the first reports of the shooting. Tank-like armored vehicles were positioned near the library. A DPS helicopter circled the campus overhead.
According to the Statesman, several people reported hearing eight to 10 gunshots at around 8:15 a.m. According to KXAN, text messages were sent to students a short time later that said the following:
At 8:28 a.m.: "Armed subject reported last seen at Perry Castaneda Library on 9/28/2010. Details to follow."
At 8:58 a.m.: "Again, armed subject reported at Perry Castaneda Library. Shelter in place. Stay where you are at. More information to follow.
At about that same time, a message on the UT website warned students to stay away from campus until the search is over.
The university is closed. A suspected shooter in PCL library is dead. Law enforcement are searching for a second suspect. If you are off campus, STAY AWAY. If you are on campus, lock doors, do not leave your building.
At 11 a.m., that message was changed to the following:
The university is open. The university is locked down. All organized classes for today, Sept. 28, are canceled. If you are off campus, stay away. If you are on campus, lock your doors and do not leave your building. Law enforcement are searching for a second suspect.
Investigators are trying to determine what led to the gunfire at the UT campus at Austin, which is one of the largest in the country with nearly 50,000 students.
Any incident involving gunfire that alludes to a shooting on the campus reminds Texans of Charles Whitman, who killed 16 people and injured 32 others during a shooting rampage from the observation deck of the university's tower on Aug. 1, 1966. Whitman's seige last about 90 minutes before he was shot and killed by police.
Check back and refresh this page for the latest details.