According to officials, the Virginia Tech officer was shot shortly before noon Eastern Time during a routine traffic stop at a parking lot.
Virginia state police announced the shooting suspect was not believed to be the person who was pulled over. They said the suspect appears to have walked into a parking lot and shot the officer during the traffic stop of a third party. Police were interviewing the person who was pulled over.
Witnesses said the suspect took off on foot toward a nearby parking lot. A person was later found fatally shot in that lot.
Police confirmed the second victim was spotted alive by a police officer and then was immediately found dead. Police say the officer did not shoot that victim, and sources say the second victim was the shooter. Virginia Tech officials said on the school's website that a weapon was recovered near the second body, identified as a white man.
At approximately 4:30 p.m. ET, law enforcement officials reported the gunman was believed to be dead. By 5 p.m. ET, school officials said there was no longer an active threat and that normal activities could resume.
Students and faculty had been asked to remain inside buildings.
Various alerts were sent out to students and the university is sending updates about every 30 minutes, regardless of whether they have any new information, school spokesman Mark Owczarski said.
Campus was quieter than usual because classes ended Wednesday and students were preparing for exams, which were to begin Friday. The school postponed those tests.
Virginia Governor Robert McDonnell released a statement Thursday afternoon, saying, in part:
"Since this news first broke we have been monitoring the situation closely and I have made available all requested state resources to Virginia Tech, including the Virginia State Police. ...
"I want to thank the multiple law enforcement agencies and all of the officers for their speedy response and focus during this difficult time. I also want to commend Virginia Tech leadership, students, faculty and staff who cooperated to efficiently respond to this emergency."
The slain police officer was identified as a 39-year-old Army veteran and father of five. The university said late Thursday that the officer was Deriek W. Crouse. He joined the Virginia Tech Police Department on Oct. 27, 2007. That was about six months after 33 people were killed at the school in the deadliest mass shooting in modern U.S. history.
About 150 students gathered silently for a candlelight vigil at Virginia Tech Thursday night.
The shooting came on the same day that Virginia Tech is appealing a $55,000 fine by the Education Department in connection with the university's response to the April 2007 shooting rampage.
The department said the school violated law in 2007 by waiting more than two hours after two students were shot to death in their dorm before sending an email warning. By then, student gunman Seung-Hui Cho was chaining the doors to a classroom building where he killed 30 more people and then himself.
The Associated Press contributed to this report.