The headstone in an old military cemetery in Kansas marks the place where William Hemings, a Civil War veteran from Ohio, was laid to rest 80 years ago. Previously unknown to Hemings family descendants, the grave may hold an important clue to one of America's most enduring mysteries: the relationship between Thomas Jefferson and his slave Sally Hemings.

After 17 months of research, Herbert Barger, a Jefferson historian in suburban Maryland, recently located the grave of the childless war veteran--the son of Madison Hemings and grandson of Sally Hemings--in Leavenworth National Cemetery.

Now Barger wants to exhume the remains to extract DNA that could be compared to Jefferson's and perhaps shed new light on the paternity of Madison Hemings, who claimed to be the son of the third president. The tests would be similar to those published in 1998 concluding that one of eight Jeffersons--including Thomas--was likely the father of Madison's brother, Eston.

To proceed, Barger needs the permission of Madison Hemings's descendants, and their answer basically boils down to this: over our dead bodies.

Oral history, they say, passed down through generations, provides all the proof they need of their ancestry. Still angry about comments made by some Jefferson descendants last May following an earlier round of DNA testing on other Hemings relatives, they have a suggestion of their own: Why not dig up the Squire of Monticello?

"My family doesn't need to prove themselves," said Shay Banks-Young, 55, a great-great-great-granddaughter of Madison Hemings who lives in Columbus, Ohio. "If they want to dig up Thomas Jefferson at the same time, maybe I'll reconsider," she added indignantly.

William F. Dalton, 35, another Hemings descendant in Ohio, said: "I believe in 'rest in peace.' . . . It really gives me the creeps to think of doing something like that."

More than a year after publication of a DNA study that further roiled what may be the country's longest-running paternity dispute and its first presidential sex scandal, mistrust still runs deep in the Jefferson and Hemings camps.

The study, conducted by retired pathology professor Eugene Foster in Charlottesville with assistance from Barger, found that a Jefferson male likely fathered Sally Hemings's youngest son, Eston.

The study's findings were widely misinterpreted as "proving" a long-rumored affair between Thomas Jefferson and his slave. In fact, the results showed that Eston could have been fathered by any one of eight Jeffersons. Some scholars argued that the tests, combined with historical evidence, showed that Thomas Jefferson was most likely the one.

But Barger and others make a case that his brother, Randolph, is more likely to have been the father. The eight possibilities identified by the DNA tests are Thomas and Randolph Jefferson, Randolph's five sons and a cousin, George.

The 1998 DNA study compared genetic material from, among others, descendants of Thomas Woodson, Eston Hemings and Jefferson's uncle, Field Jefferson. But no DNA was drawn from descendants of Sally Hemings's second-youngest son, Madison, because there is no unbroken line of male descendants that could yield a valid Y chromosome comparison.

With the location of Madison Hemings's remains still unknown, the discovery of his son William's grave in Kansas offers the first possibility for such a test, Barger said.

Said Barger, a 73-year-old retired Air Force master sergeant who has studied the Jefferson family for 25 years: "I just wish they would give their permission and let the chips fall where they may."

A DNA match would put Madison Hemings's descendants in the same position as those of Eston Hemings, showing only that "some Jefferson" was the father. "It will never be clear-cut that it was Thomas," Barger said.

As for exhuming the remains of Jefferson from his Monticello grave, DNA from the former president might have some scientific value but probably would not be any more useful in determining the paternity of Sally Hemings's children than the existing Jefferson-line samples, said Foster, author of the 1998 study.

Barger, a resident of Fort Washington, said he found William's grave after tracing him to a home for disabled veterans in Leavenworth, where he died in 1910 at age 63. As a teenager, William Hemings served in an Ohio infantry unit in the Civil War. His father, Madison, had publicly described himself as a son of Thomas Jefferson and said his mother, Sally, was Jefferson's "concubine" in France in the late 1780s.

Barger doubts that, arguing that the Hemings children more likely were fathered by Jefferson's younger brother, Randolph, and possibly others, including one of Randolph's sons, who were young men when Sally Hemings was bearing children at Monticello.

Hemings family members such as Dalton attribute such denials in part to racism; his own feelings about Jefferson evince the ambivalence of many African Americans toward ancestors who owned slaves.

"I feel Jefferson was one of the greatest men," Dalton said. "If it wasn't for him, I wouldn't be here. So how can I hate him?"

CAPTION: This is the headstone of William Hemings, Civil War veteran, son of Madison Hemings and--possibly--grandson of Thomas Jefferson.