One member of the D.C. National Guard was killed and six others injured in predawn darkness yesterday when a driverless heavy duty military truck rolled down a training camp hillside and demolished the men's tents.

Authorities at Camp A. P. Hill, in Virginia, where the incident occurred, called it an accident, but said that a member of the victim's unit was taken into custody pending further investigation.

The man who was killed was indentified as Pvt. William L. Chase, 21, a member of the Guard's 276th Military Police Company. Chase, 800 Bellevue St. SE, died of cardiac arrest after apparently being hit by the truck.

The other six men were injured as they scrambled to flee their collapsing tents on the sprawling 77,000 acre base 20 miles south of Fredericksburg, Va., and 75 miles south of Washington.

Authorities said the truck was started before it began careening downhill, but they gave no further details.

A spokesman said "it was felt that no criminal intent was involved."

The name of the man being held was not disclosed.

"It's certainly a tragic thing," said Lt. Col. Richard Cheney. The D.C. guard unit had arrived at the base Friday night for weekend maneuvers. d"You always run the risk of danger when deploying troops in the field, but I can't remember anything like this happening before," Cheney said.

The D.C. Guardsman were at the Virginia base for their annual qualification in the use of the standard Army M-16 rifle.

The 276th is trained for active duty in national emergencies and for crowd control in civil disturbance.

The tents, permanently erected for visiting troops, held 20 men each. They were set up in an open area surrounded by woods. The slope down which the truck came "really wasn't that much of an incline," said Derek Farmer, a captain in the Bowling Green, Va., rescue squad.

But, he added, the six-wheel vehicle "just mowed down the tents. There were upended cots all over the place."

The six injured men were treated at Mary Washington Hospital in Fredericksburg for bruises and sprains and then released.

Guard officials refused requests for interviews with them and said they were expected to resume training and return tonight to Washington.

They were listed as Sgt. George Hamilton, 4212 Russell Ave., Mount Rainier; Sgt. Timothy L. Ellis, 35, 9812 Ambler La., Upper Marlboro; Pvt. Carlton Whittingham, 18, 6303 Lee Pl., Cedar Heights; Sgt. Robert Wardtrick, 31, 2120 Brooks Dr., Suitland; Specialist 4.C. Bobby S. Scott, 31, 4352 Lee Hwy., Arlington, and Sgt. Nathaniel Washington, 37, 1327 Barnaby Terr., SE.