Police on Friday identified the gunman who killed a police officer at Virginia Tech, scene of a deadly mass shooting in 2007, and then killed himself as a 22-year-old man attending a nearby college.

Virginia State Police said in a statement that the man responsible for Thursday's shooting, Ross Truett Ashley, was a part-time student at Radford University.

The crime at the 31,000-student Virginia Tech revived memories of the April 2007 bloodbath in which 32 people were shot dead by a student who then killed himself -- the deadliest shooting incident by a single gunman in US history.

State police said there was "no prior connection" between Ashley and campus police officer Deriek Crouse, who was slain when the gunman walked up to his unmarked patrol car during a "routine traffic stop" involving a third person.

The 39-year-old Crouse -- a US army veteran and father of five children and step-children -- "was not able to return fire or fire his weapon," state police spokeswoman Corrine Geller earlier told reporters.

Ashley has been connected to the theft at gunpoint of a white 2011 Mercedes SUV on Wednesday, the state police statement said. That vehicle was found Thursday on the Virginia Tech campus.

Geller said that after killing Crouse, the gunman then went to a nearby greenhouse and changed his clothes, leaving a backpack containing a pullover top and wool cap behind.

About 30 minutes later, a local county deputy sheriff spotted a man alone and "acting a bit strangely" in a fenced-in campus parking lot known as the Cage, about a half-mile (one kilometer) away, Geller said.

When the deputy sheriff caught up to him, the individual was deceased from "what appears to be a self-inflicted gunshot wound," she said, adding: "Nobody actually witnessed him taking his own life."

The bodies of Crouse and Ashley have been transported to the morgue, where autopsies will be carried out, police said, adding the investigation was ongoing.

Virginia Tech associate vice president Larry Hincker said the university had, once again, been the scene of "a wanton random act of violence."

"We have experienced this tragedy before," he said.

Crouse joined the campus police force six months after Seung-Hui Cho, 23, an English major whose family emigrated from South Korea to the United States when he was young, gunned down 32 people in April 2007 before committing suicide.

Twenty-five others were wounded in that attack.

A subsequent inquiry found that Cho suffered from anxiety disorder and depression in high school, and faulted educators and mental health professionals for not acting on his deteriorating condition in university.

Thursday's shootings prompted a campus-wide lockdown a day before the start of final exams for the fall term. Students planned to stage an outdoor vigil for the slain officer Friday after sunset.

The university, as big as a small American city, is situated in Blacksburg, 220 miles (355 kilometers) southwest of Washington.

Geller said the driver of the silver Honda automobile that Crouse had stopped was a male Virginia Tech student who has been "extremely cooperative" in the investigation.

Of the shooter, who was captured by a video camera affixed to Crouse's patrol car, Geller said: "We are very confident that he was the only individual involved in this."