Video report by John Salazar.

A gunman who fired shots on the University of Texas at Austin campus has been identified as 19-year-old Colton J. Tooley, a student of the university. Tooley was a sophomore mathematics major from Austin.

Police say Tooley fired at least four rounds on 21st Street, before running to the sixth floor of the library and turning the gun on himself shortly after 8 a.m.

According to EMS officials, no one else was wounded.

Late Tuesday afternoon, officers from the Austin and UT police departments continued their investigation into the shooting at a house on Western Drive in South Austin. It’s believed he lived at the location with his parents.

Crime scene tape was up around the neighborhood, and officers asked residents to produce identification before they could access their homes.

Officers were seen removing boxes and papers from the home.

Authorities say Tooley acted alone in the shooting. Early in the investigation, authorities had worked multiple leads and searched the campus for a second suspect.

"When reports come in, we have to take them seriously," Acevedo said. "We owe it to the parents and students to be safe rather than sorry."

Austin Police Chief Art Acevedo addressed the media around 10:45 a.m. Sirens could still be heard around campus. Throughout campus, police could be seen with their guns drawn.

Police were methodical in their search and also conducted secondary searches of buildings in order to eliminate any worry of explosives on campus.

Around 11:40 a.m., campus officials began gradually opening the campus as they tightened the perimeter around the main crime scene, the Perry-Castaneda Library.

Loudspeakers around campus instructed students on where to catch shuttle buses. The students were directed to evacuate the campus and head north. All dorms were reopened, but classes and on-campus events were cancelled for the day.

Neil Grey was also on campus when the shootings happened. He said he saw a man wearing a black three-piece suit and a black ski mask running down 21st Street. As the man ran, he fired an AK-47 in all directions near the Littlefield Fountain.

Oscar Trevino's daughter is an employee at UT. His daughter was walking to her office when she heard shots fired and saw the gunman. She was frantic when she called her dad.

"You're hopeless. You just hope that God takes care of her, and I'm just glad she was able to run away, and the guy apparently took care of himself instead of anybody else," Trevino said. "And I thank God that's what went on today."

Trevino's was able to get in contact with his daughter. She was shaken up but okay and safe.

A CapMetro bus with UT students was told to pull over and evacuate after the driver heard 'pops.'

News 8’s Maureen McCann was on the third floor of the engineering school, where she said she could hear sirens go by.

"The lab proctor has been downstairs and said everyone was told to get under desks and tables," McCann reported.

An employee of the library said the detectors at the front door are to keep people from stealing books, and not metal detectors.

Classes are expected to resume as normal, tomorrow.

In the video above, Austin Police Chief Art Acevedo talks about the shooting at a Tuesday morning press conference.