MAZAR-E-SHARIF, Afghanistan ? Each stab of the shovel brings up more disturbing finds: skulls, bones covered by bits of clothing, clumps of hair.

When United Nations investigators resume inquiries  perhaps as early as next month  this pit in a corner of a vast stone quarry may reveal an important part of a wider story of alleged atrocities by the Taliban and by the U.S.-backed alliance that toppled them.

The pit, about 6 miles west of Mazar-e-Sharif, was used by the Taliban as a mass grave for members of the Hazara minority who were systematically killed after the northern city fell in 1998, Hazara leaders allege.

The Hazara are followers of the Shia branch of Islam, which is dominant in Iran and a few other places, but which the Sunni Muslims who made up most of the Taliban considered a flawed version of Islam.

Hazara leaders claim their group, about 10 percent of Afghanistan’s population, suffered the worst atrocities at the hands of the Taliban. They claim as many as 15,000 Hazara were killed in a religious-motivated slaughter in Mazar-e-Sharif and other parts of the country.

There is no independent source yet to measure the Hazara claims. The Taliban prevented international investigations in Afghanistan, but the new U.N.-brokered interim government has promised full access to inquiries.

Asma Jehangir, the U.N. special investigator for extrajudicial executions, said she hopes to begin work in Afghanistan next month. The U.N. Human Rights Commission, meanwhile, is expecting a report by late March from its special investigator for Afghanistan, Kamal Hossain.

The Hazara claims, Jehangir noted, are just a piece of a complex web of alleged battlefield atrocities, ethnic reprisals and revenge slayings.

The United Nations and other rights groups have also cited accusations aimed at anti-Taliban forces, including the alleged execution of as many as 2,000 Taliban in 1997 in Mazar-e-Sharif and the killings of about 100 retreating Taliban fighters in November.

Last year, New York-based Human Rights Watch called for an inquiry into reports that the Taliban massacred as many as 300 Shiite civilians in central Bamiyan province. At the time, the Taliban denied the charges.

The evidence in the quarry is fragmentary, but appears to fit with witness accounts.

They claim Taliban soldiers spent days in September 1998 tossing bodies  mostly men but also some women and children  into a pit about 20 feet on its sides and 16 feet deep. Hazara leaders believe the site could contain hundreds of bodies.

“The smell was horrible,” said Jahn Mohammad, 17, an ethnic Tajik who worked at the quarry. “The Taliban left after some days and we came and covered the bodies. It was impossible to count them. The pit was very full.”

Another Tajik, a 22-year-old farmer named Nasir, said the Taliban brought the dead piled on a flatbed truck and “just threw the bodies into the pit one by one.”

Golum Abbas Akhlaki, the political chief of the main Hazara group, Hezb-e-Wahadat, plunged a shovel into the loose soil. Each scoop turned up bits of human remains.

“When we dig up the entire area, then we will know the real count,” he said. “It will be a big number, I am sure of that.”