Kent State University students held a vigil Saturday where four of their counterparts from another era were shot dead exactly 21 years earlier by Ohio National Guardsmen during an anti-Vietnam War protest.

The events of May 4, 1970, permanently scarred the campus. But the college south of Cleveland hasn't tried to cover up its past; it has taken an active role in remembering the day and the era.On the 20th anniversary last year of the shooting that left four dead and nine wounded, a memorial was dedicated.

And on Saturday, a 12-hour vigil was held at the spots where the four mortally wounded students fell to the ground in the parking lot of Kent's journalism building.

Numerous investigations never conclusively established why the guardsmen fired. Some witnesses said a lieutenant either gave a verbal order or made a gesture that was misinterpreted.

Others said one guardsman fired, followed by the volley a split-second later by the rest - perhaps in reaction to rumors sweeping the campus that some students had weapons. No weapons were ever found.

All four of those killed - Allison Krause, 19; Jeffrey Miller, 20; Sandra Scheuer, 20; and William Schroeder, 19 - and most of the rest of those wounded were in or near a parking lot, between 100 and 130 yards from the guardsmen.