Last Saturday, the head of the international inspection force in Kosovo confronted an unspeakable horror on a hillside above a poor farming village in southern Kosovo. As he walked up the steep ravine, he encountered a headless corpse, then the bodies of three elderly farmers with gunshot wounds to their heads, and finally the bodies of 23 men. As he picked his way among the blood-spattered corpses lying beneath thin blankets at his feet, William Walker said his mind flashed to an episode almost exactly 10 years before, in war-torn El Salvador. It was the day when military forces of the U.S.-backed government had brutally murdered six Jesuit priests, their housekeeper and her daughter on a university campus in the country's capital. Walker, at the time a 52-year-old U.S. ambassador, was deeply scarred by an ensuing controversy over his reluctance to mete out responsibility for the murders. The media, the Jesuit order and liberal U.S. politicians said Walker was covering up the security forces' involvement in the massacre, and his silence was seen as a byproduct of Washington's tacit backing of human rights abuses by the Salvadoran government in its battle against leftist rebels. Standing on the hillside last weekend above the Kosovo village of Racak, with a pack of reporters demanding his appraisal of the massacre, Walker reminded himself that he "would hate like hell to be accused of that again," he said in an interview today. So he resolved to hold a news conference at the inspectors' headquarters in Pristina, Kosovo's provincial capital, that evening. There, Walker poured out his emotions. "I do not have words to describe my personal revulsion . . . at the sight of what can only be described as an unspeakable atrocity," he said. "Although I am not a lawyer, from what I personally saw, I do not hesitate to describe the crime as a massacre, a crime against humanity. Nor do I hesitate to accuse the government security forces of responsibility." Walker's remarks drew the ire of Yugoslav President Slobodan Milosevic, who said that at least some of the victims were uniformed ethnic Albanian rebels who were killed in a battle with government forces. Milosevic ordered Walker expelled from the country -- a decision he suspended late Thursday night following protracted talks with U.S. officials. Walker's decisiveness last weekend ultimately was supported by the official report of the Kosovo Observer Mission he leads, which concluded, as he did, that Yugoslav forces were responsible for the atrocity. The 700-member mission, which is run by the Organization for Security and Cooperation in Europe, is charged with overseeing an October accord in which Milosevic agreed to withdraw security forces from Kosovo. Interviewed in his office here today, Walker said he decided to see the evidence for himself after hearing on the evening of Jan. 15 that fighting had been fierce in Racak. His chief of operations, British Maj. Gen. John Drewienkiewicz, told him there were reports that many people had been killed. The government's attack on the ethnic Albanian, rebel-held village followed a series of incidents in the region in which government troops had been ambushed by guerrillas of the Kosovo Liberation Army. At least three government troops were killed in the incidents. According to the report, by Jan. 12 Yugoslav army forces had begun to move tanks and other armored vehicles, some towing artillery, into the area. The arrival of forces began to sow terror among the local populace, and more than 1,000 civilians fled the area. Skirmishing between rebels and government forces began on Jan. 14, when OSCE inspectors heard "the sound of tank, mortar, heavy machine gun and small arms fire," according to the report. The army prevented the inspectors from getting close to the fighting. On Jan. 15, the day the massacre occurred, inspectors in the area reported a "serious deterioration of the situation," after seeing houses burning in Racak and another village and watching tanks and armored vehicles "firing directly into houses" nearby, the report said. Residents told of men in the village being segregated from women and children, with 20 of them being "taken away." Fearing the worst, teams of inspectors and specialists from the organization's human rights division converged on the village early the next morning. Walker was among them. "I talked to several villagers . . . and started up the hill," Walker said. "In a gully above the village, I saw the first body. It was covered with a blanket, and when it was pulled back, I saw there was no head on the corpse -- just an incredibly bloody mess on the neck. Somebody told me that the skull was on the other side of the gully and asked if I wanted to see that. But I said, No, I've pretty much got this story.' " Up the hill, Walker came upon three more bodies. "They looked like older men, with gray hair or white hair, and were unshaven," he said. "They were all dressed in what Latin Americans would call campesino clothes, with rubber boots and the three to four layers of shirts and sweaters that farmers wear to keep warm in this weather. They had wounds on their heads, and there was blood on their clothes." Further on was the largest group of bodies. "I didn't count them. I just looked and saw a lot of holes in the head -- in the top of the head and the back of the head," Walker said. "A couple had what appeared to be bullet wounds knocking out their eyes. I was told there were other bodies further up and over the crest of the hill, and I was asked by journalists and inspectors if I was going to go up and see the rest. I said, I've seen enough.' " CAPTION: Serbian police officers earlier this week patrol the streets of Racak, where an international mission accuses the government of a massacre. ec CAPTION: OSCE Chairman Knut Vollebaek (left) and Kosovo mission chief William Walker answer reporters' questions. ec