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Authorities investigating the deadly shooting Thursday at Virginia Tech say there is no apparent connection between the still-unidentified gunman -- who apparently took his own life -- and his victim, a 39-year-old campus police officer and father of five.

The male suspect shot and killed Virginia Tech police officer Deriek Crouse in a parking lot Thursday afternoon before killing himself with the same handgun about a half-mile away, school officials said during a press conference Friday.

Crouse was killed after pulling over a Virginia Tech student in a traffic stop at around 12:15 p.m. Authorities said the gunman -- who was not involved in the traffic stop -- walked into the parking lot adjacent to the Cassell Coliseum and ambushed the officer. Crouse was unable to return fire, according to officials.

Virginia State Police spokeswoman Corinne Geller said authorities are "very confident" they know the identity of the shooter but are waiting to release his name until his next-of-kin is notified. They believe he acted alone.

Geller would not comment on whether the assailant had any known criminal record or history of mental illness.

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    She said the motive in the shooting is still under investigation. She also would not confirm reports that the shooter stole a vehicle in Ratford, Va., before driving to the Virginia Tech campus in Leesburg.

    "We have not made an absolute connection that he stole the vehicle," Geller said.

    Larry Hincker, Virginia Tech's associate vice president of university relations, confirmed that the suspect was not a student at the school.

    The shooting took place on the same day Virginia Tech officials were in Washington, fighting a government fine over their alleged mishandling of the 2007 bloodbath where 33 people were killed in the deadliest shooting rampage in modern U.S. history.

    Before it became clear that the gunman in Thursday's attack was dead, the school applied the lessons learned during the last tragedy, locking down the campus and using a high-tech alert system to warn students and faculty members to stay indoors.

    Crouse was a US army veteran and father of five children and stepchildren who had served on the university's police force for four years.

    Shortly after Crouse was shot, police found in a parking lot a man with a gunshot wound and a gun nearby. Authorities confirmed Friday that it was the same handgun used to kill Crouse.

    Geller said the suspect fled to a greenhouse on campus, where he changed his clothes. She said a deputy found him with what appeared to be a self-inflicted gunshot wound.

    Virginia Tech police chief Wendell Flinchum said during the press conference that Crouse "was a friend to many in our department."

    "His death is a tremendous loss to our department," Flinchum said.

    A woman who answered the door at the Crouse home at the end of a three-unit townhouse building Thursday night said it wasn't a good time to talk, and they were trying to get the children to bed. A group of people were sitting around a table inside.

    Rusty Zarger of Lynchburg, a former neighbor, remembered Crouse as polite, family-oriented and self-assured. "He was a standup guy," said Zarger, whose two young daughters used to play with Crouse's sons at the townhouse complex where they lived. "He was very mild-mannered, very confident. You could tell he was strong in believing in himself, but very comfortable."

    Virginia Tech police chief Wendell Flinchum said during the press conference that Crouse "was a friend to many in our department."

    "Words can’t express the loss we’ve experienced within our own department," Flinchum said.

    Many students were preparing for exams when they were suddenly directed to hunker down during the shooting Thursday. Heavily armed officers swarmed the campus as caravans of SWAT vehicles and other police cars with emergency lights flashing patrolled nearby.

    "A lot of people, especially toward the beginning were scared," said Jared Brumfield, a 19-year-old freshman from Culpeper, Va., who was locked in the Squires Student Center.

    The university sent updates about every 30 minutes, regardless of whether they had any new information, school spokesman Mark Owczarski said.

    Harry White, 20, a junior physics major, said he was in line for a sandwich at a restaurant in a campus building when he received the text message alert.

    White said he didn't panic, thinking instead about a false alarm about a possible gunman that locked down the campus in August. White used an indoor walkway to go to a computer lab in an adjacent building, where he checked news reports.

    "I decided to just check to see how serious it was. I saw it's actually someone shooting someone, not something false, something that looks like a gun," White said.

    The campus was quieter than usual because classes ended Wednesday. About 20,000 of the university's 30,000 students were on campus when the officer was shot. Exams, set to begin Friday, were postponed.

    The shooting came soon after the conclusion of a hearing where Virginia Tech was appealing a $55,000 fine by the U.S. Education Department in connection with the university's response to the 2007 rampage.

    The federal agency said the university violated the law 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 department said the email was too vague because it mentioned only a "shooting incident," not the deaths. During testimony Thursday, the university's police chief, Wendell Flinchum, said there were no immediate signs in the dorm to indicate a threat to the campus. He said the shootings were believed to be an isolated domestic incident and that the shooter had fled.

    An administrative judge ended the hearing by asking each side to submit a brief by the end of January. It is unclear when he will rule.

    Since the massacre, the school has expanded its emergency notification systems. Alerts now go out by electronic message boards in classrooms, by text messages and other methods. Other colleges and universities have put in place similar systems.

    The Associated Press contributed to this report.