On May 4, 1970, after days of unrest over America's invasion of Cambodia during the Vietnam War, student protesters at Kent State University clashed with Ohio National Guardsmen. The guardsmen opened fire, killing four students and wounding nine others.
"Some people here believe the Guard, under the pressure of a rock throwing attack, fired its weapons indiscriminately, killing four people," CBS News correspondent Ike Pappas reported from the scene.
The protests began after President Richard Nixon announced the invasion on April 30th. Students rallied on campus over the next four days, at one point setting the ROTC building on fire and rioting in downtown Kent.
With the local police force stretched thin, the Ohio National Guard was called in, and school officials banned a rally planned for May 4th due to the potential for more violence.
But the students still gathered as planned. After repeated warnings to disperse, tear gas canisters were fired into the crowd. A group of students began throwing the tear gas, as well as rocks and sticks, back at the guardsmen.
"A few kids were throwing sticks and stones, but that was only a handful, not more than ten, fifteen," one student told CBS News.
Eventually, more than seventy troops advanced on the students. Tensions escalated, and twenty-eight guardsmen fired their weapons into the crowd of demonstrators.
"All of a sudden I heard them shooting, then I saw people dropping to the ground. Then I dropped to the ground," the student said.
It is still unclear exactly why the guardsmen decided to fire into a group of unarmed students. Some testified during the investigation that they felt they were being surrounded, and their lives were in danger.
Another theory was that they fired after a sniper opened fire on the troops from a rooftop nearby, as the then-Adjutant General of the Ohio National Guard said in a statement to the New York Times on the day of the shooting.
"What the investigators have to determine then is whether indeed there was a sniper, and whether the Guard was justified in firing its weapons," reported Pappas.
"This should remind us all once again that when dissent turns to violence it invites tragedy," President Nixon said in response to the tragic events.
Instead of leading to a decrease in protests around the country, they actually escalated even further. Many colleges and universities shut down their campuses for fear of similar violence. Kent State closed after the shooting, and didn't reopen until six weeks later for summer classes.
Protests wound down after President Nixon began to withdraw U.S. troops from Vietnam, but the shooting remained as a lasting symbol of a nation deeply divided by the war. The unrest later inspired the Crosby, Stills, Nash and Young song "Ohio."
Eight guardsmen were eventually indicted by a grand jury, but the case was later dismissed over a lack of evidence.