Roanoke Firearms owner John Markell holds a Glock 9 mm pistol similar to the one sold in his gun shop 36 days ago to the Virginia Tech shooting suspect Cho Seung-Hui

A student with a cellphone camera watched police approaching and heard gunshots inside the classroom building where the horrific shooting rampage was taking place.  Monday's gunfire killed 33 people -- 32 students and instructors plus the gunman, who took his own life.  The tragedy at Virginia Tech also brought back memories of other school massacres.

Eight years ago this week (April 20th), two boys at Columbine High School in suburban Colorado shot and killed 12 students and a teacher.  Last October, an armed gunman killed six girls in a one-room Amish schoolhouse in a rural part of Pennsylvania.

In the wake of the massacre in Virginia, White House spokeswoman Dana Perino said President Bush continues to believe in Americans' constitutional right to have firearms, within the law.

"If there are changes to the president's policy, then we will let you know,” she said. “But we've had a consistent policy of ensuring that the Justice Department is enforcing all of the gun laws that we have on the books, and making sure that [violators] are prosecuted to the fullest extent of the law."

Police say the Virginia Tech gunman was 23-year-old Cho Seung-hui, born in South Korea but a resident of the United States since childhood.  Cho was entitled to buy a pistol, under gun laws in the state, since he was never found guilty of any serious criminal activity.

The best-known U.S. advocacy group that opposes more restrictive gun-control laws is the National Rifle Association, or NRA.  The group's spokesman, Bill Powers, says it is a citizen's fundamental right -- as stipulated in the U.S. Constitution -- to keep and bear arms.

"There are politicians, special-interest lobby groups who frankly don't like the 2nd Amendment [to the Constitution], don't like firearm owners, no matter how lawful and peaceful they are.  They don't like firearms, they don't like the great history and tradition of freedom in the 2nd Amendment and the Bill of Rights that was part of the forging of our nation," says Powers.

Nancy Hwa speaks for a group called Handgun Control, which wants more stringent laws about gun ownership:

"If you look at the wording of the 2nd Amendment, it talks about 'the well-regulated militia.'  Nowadays, that's the National Guard.  In terms of maintaining a national guard -- that's what the 2nd Amendment refers to.  It does not mean that everybody has the right to own an Uzi [submachine gun]."

The Federal Bureau of Investigation says that, as of late 2005, background investigations mandated by current laws have barred almost a half million people from purchasing firearms.  Federal, state and local law-enforcement agencies have performed checks on more than 50 million Americans seeking permission to buy guns.