We have updated this story as details emerge

A police officer was shot and killed early this afternoon on Virginia Tech's campus during a routine traffic stop, putting the campus on lockdown for several hours. The suspect fled the scene, and police later found another body, along with a gun, on campus grounds.

NBC reported that the second body is believed to be the shooter and that the recovered weapon was his own, but police would not confirm that identification at a press conference Thursday evening, saying the investigation is still pending.

"Today tragedy again struck Virginia Tech in a wanton act of violence," said Charles Steger, president of Virginia Tech at the press conference. "Our hearts are broken again for the family of our police officer and we extend our deepest sympathy and condolences." He said counseling will be available for university students and staff.

Robert Carpentieri, of the Virginia state police, said at the presser the slain police officer stopped a driver for a traffic violation when a third party approached the officer and shot him. Virginia Tech deputy chief of police Gene Deisinger said the officer was a four-year veteran on the campus force. The officer's identity is being held pending notification of his extended family. It is believed to be the first time a Virginia Tech university police officer has been killed in the line of duty.

Earlier this afternoon, students were asked to stay indoors as hundreds of police officers searched and secured campus buildings and public areas for the gunman, who was reported to be a man wearing a maroon hooded sweatshirt. (The Virginia Tech colors are orange and maroon.) Area K-12 schools were also on lockdown, but later released students. The university lifted the lockdown order at 4:30 p.m.

Deisinger said that full lockdown of the 2,600-acre Virginia Tech campus as it is popularly understood "is an impossibility." Virginia Tech is located in Blacksburg, in southwest Virginia.

Story continues

"What I observed was significant cooperation," he said.

Students were not in class today because exams were set for tomorrow, Virginia Tech spokesman Mark Owczarski said at a mid-afternoon press conference. Those exams are now postponed. "It's a very tragic day," Owczarski said.

Lerone Graham, a reporter for local newspaper the Roanoke Times reported around 2:00 p.m. via Twitter that, "students scarce now around campus; sirens sounding constantly." Later reports of more gunshots on campus were unfounded, the university said.

Nathan Latka, a former Tech student who works in an office near Squires Student Center, told Yahoo News he first heard the campus sirens go off and then received a text message from the university warning him about the shooting. "That's when I realized something was wrong," he says. Latka watched a student emerge from Squires during the lockdown as five police officers pointed assault rifles at him. The student was not arrested.

In 2007, a Virginia Tech student killed 32 people and himself during a shooting rampage.

Virginia Tech began the appeals process for a $55,000 federal fine levied for its handling of the 2007 shooting spree this week in Washington. (Tech's police chief was testifying today and was not on campus earlier.) The government says the university did not warn students that a shooter was on the loose in a timely manner, in violation of a 1990 safe campus law known as the Clery Act. The parents of two wounded Tech students said their children would have stayed indoors and avoided injury if the school had notified them, according to the Roanake Times. The school says it complied with the law.

Tech upgraded its security system after the 2007 shooting. Owczarski said the university can reach students via text message, email, classroom electronic message boards, campus sirens, and a downloadable application called "desktop alerts." Students were alerted about the shooting today soon after it occurred.

Below, you can an ABC News special report on the lockdown:

You can watch Virginia Tech Director of News & Information Mark Owczarski's afternoon remarks on the shooting below:



Other popular Yahoo! News stories:

• Jon Huntsman to Americans: Trust me

• Women left the workforce in droves last month

• Iran releases video of downed U.S. spy drone