A still-unidentified gunman brought Virginia Tech University to a standstill this afternoon, leaving a campus police officer and one other person, reported by some outlets to be the assailant, shot dead.

Students and members of the neighboring Blacksburg community spent four hours holed up on campus, as a lockdown was enforced until officers located the gunman. That alert was lifted by 4:30 p.m., according to the school's Web site and a press conference soon followed.

At one level, the loss of any human life is a tragedy, said Virginia Tech President Charles Steger. This brings back some difficult memories of the past.

The Virginia Tech police officer, one of 53 monitoring the campus, was conducting a routine traffic stop when the assailant came and shot the officer, then fled the scene. Police were quick to note the gunman was not the driver, but a third party. Witnesses called in the incident. Officers then spotted a person of interest, who fled into the I Parking Lot, more commonly known as the cage. By the time they reached him, that person was found dead from a gunshot wound. A gun was also found, though the location of the weapon was not confirmed.

Sgt. Bob Carpentieri of the Virginia State Police offered little information during the press conference, as the dual crime scenes were still being investigated. Matters like whether or not the second victim was the actual gunman, names, age or descriptions could not be clarified.

I don't think there's a motive at this time, Carpentieri said. That's still being investigated.

The incident comes during the middle of student preparations for finals, before winter recess. All finals scheduled for tomorrow were canceled, with a revised schedule to be released shortly.

At the time of the shooting, Virginia Tech's alert system kicking in, telling students to stay indoors.

Stay inside. Secure doors. Emergency personnel responding, the site read at the time.

The school underwent a similar trauma four years ago, when Cho Seung-Hui shot 32 people dead before committing suicide.

The specter of the shooting reemerged well before Thursday's shooting, as school officials appeared in court to fight fines of $55,000 for not alerting students quickly enough the day of the 2007 shooting. Steger was satisfied with the school's response this time around.

The suspected gunman was described as a white male wearing gray sweat pants, a gray hat with neon green trim, maroon hoodie and backpack. Carpentieri said the commonality of the description led to many false leads.