The man was not a Virginia Tech student and had no known connection to Officer Deriek W. Crouse, 39, officials said. Police said they were still confirming the man's identity and investigating the motive for the shooting.
Ballistics testing confirmed the same weapon was used in both shootings, police said.
Shortly after noon on Thursday, Crouse had a vehicle stopped in a campus parking lot when he was approached a man and fatally shot while still in his car, police said. The man then fled.
About 30 minutes later, a Montgomery County sheriff's deputy saw a man acting suspiciously in a parking lot about a half a mile/0.8 km away from the first shooting. After briefly losing sight of the man, the deputy found him dead on the ground with a handgun nearby, police said.
Police later recovered a discarded backpack on campus with clothing inside that was similar to that worn by the man seen in video taken by Crouse's patrol car.
The man apparently changed clothes on the way to the second parking lot, Virginia State Police spokeswoman Corinne Geller said at a media briefing held on Virginia Tech's campus. Police are investigating writing found on a wall near the backpack, she said.
Officials did not lift the lockdown on campus until later on Thursday afternoon because they could not immediately identify the man as the shooter and were still investigating tips from the public, Geller said. The body did not have identification on it, but police found an ID in the backpack.
Officials are still trying to determine the man's whereabouts before the shooting, Geller said. It's likely he is connected to a vehicle that was stolen in nearby Radford, Virginia, but police haven't confirmed that, she said.