SOFIA, BULGARIA -- A school for the blind changed abruptly here one winter into a political prison. Margarita Stoyanova, 14 years old at the time, lived just across the street. She could not help but see and hear what the school had become.

Every morning at 6, horse-drawn carts rolled up to the building's gate. Blood-splattered corpses were dragged out the front door and loaded one on top of another. At night, screams echoed through the neighborhood. Police often visited Stoyanova's house, ordering the family to keep its curtains drawn.

One December afternoon in 1944, the girl caught sight of her own father, looking pale and battered, staring down at her from a third-floor window in the school-turned-prison. He held his index finger to his lips, warning her to silence.

Her father was later taken away to a concentration camp, where he was last seen alive in 1950. Her mother went to the local police station on the day her husband was first arrested. There she was gang-raped. After that, two Ministry of Internal Affairs officials took up residence in the family house, helping themselves to food and paying no rent.

The girl herself, now 60 years old, was taken off to a labor camp. She was given a pair of overalls and ordered to tend fields of sunflowers from 4 a.m. to 7 p.m. It was called "reeducation in communism and prosperity."

Only this spring, with free elections coming in June, has Bulgaria opened the curtains on its Soviet-style gulag of labor and concentration camps. It took a democratic revolution, with tens of thousands of people chanting in the streets, before the government would investigate a secret that Bulgarians had been whispering about for four decades.

At least 86 camps operated here from 1944 to 1962, according to evidence uncovered in the past three months. Although there are no detailed records, Western diplomats here have seen credible evidence that about 180,000 people passed through the camps and that about 18,000 of them died. Unmarked mass graves have been uncovered regularly across the country for the past two months. Bulgaria's chief prosecutor warned citizens in April not to dig up graves on their own initiative "even if their motives were noble."

Camp survivors and relatives of victims have told government newspapers that thousands of bodies were trucked to uninhabited islands in the Danube where they were eaten by wild boars.

"They say the dead bodies were not fed to the pigs, but I have personally seen a pig drag a human hand," Angel Angelov, who spent five years in labor camps on the Danube, told the government weekly Sofia News.

In a report released last month, a government-appointed special commission described the camps as "extremely cruel phenomena" run by people "with low professional and human qualities." The commission said "politically inconvenient" victims were subjected to "strenuous labor, malnutrition, insufficient rest, poor medical care . . . regular beatings, and the humiliation of personality and dignity."

Bullet-pierced skulls pulled from unmarked graves have become campaign fodder in Bulgaria, where an inexperienced and divided opposition is struggling to win votes away from the well-organized reform Communists who orchestrated this country's top-down revolution last November.

Yet the flood of appalling disclosures about the camps appears not to have discredited the reformed Communist Party, which earlier this year renamed itself the Bulgarian Socialist Party.

The leadership that engineered the coup that dumped Todor Zhivkov, who had been the world's longest-serving Communist leader, has condemned the concentration camp crimes, blamed them on Communists who are now out of power and vowed never to use repression against citizens.

In doing so, the reformers appear to have distanced themselves from the crimes of the party. Opinion polls this month showed the ruling party with a substantial lead over the opposition. Polls show that the five most popular politicians in the country are all reform Communists.

"The opposition has simply overdone it with the skulls and bones. There is an over-saturation with terror," said Chavdar Kuranov, a member of the party's Supreme Ruling Council.

The Union of Democratic Forces, the opposition umbrella group, agrees that it has turned some voters off with posters and campaign slogans about the camps.

"It promotes frustration and negative feelings," said Petko Simeonov, a sociologist who is a key strategist for the opposition. "We will not stop campaigning on this issue. But we will decrease it relatively."

A partial explanation for the somewhat benumbed national reaction to publicity about the camps can be found in the history and traditions of this small Balkan country of 9 million people.

Bulgaria was for 45 years the most slavish and quiescent of Soviet satellites. Russians are still seen as liberators who in 1878 helped free Bulgaria of 500 years of Turkish rule.

Complementing a sympathy for all things Russian, there is almost no tradition in Bulgaria of a national government that is anything other than brutal, intolerant and undemocratic. Historian Paul Lendvai has written that the recent history of Bulgaria is a "chronicle of unfulfilled hopes and cheated expectations that have bred a deep-rooted psychology of defeat."

"The shadow fell across this country," said Jean Solomon, a Bulgarian journalist and opposition activist who has helped excavate several mass graves this year. "Everyone was scared to death. Everyone tried to stick to the rules. For intellectuals, it was creative death. These camps have had a great influence on the political and cultural life of Bulgaria."

Margarita Stoyanova refused to speak in a voice louder than a whisper. The tall, gray-haired woman has lived her entire life under the shadow of what happened to her father, her mother and herself in the 1940s and '50s.

"We had a very beautiful family. My father worked for the Ministry of Finance in wine production control. My mother was from a prosperous family. Her parents owned land and two mills. When the militia came for my father in October 1944, there was no specific charge. The militiaman told my father, 'You are a fascist and you must die,' " Stoyanova said.

After Sept. 9, 1944, when Communists seized power in Bulgaria, the Ministry of Internal Affairs launched a campaign to liquidate all "class enemies." In addition to members and known supporters of the former government, these "enemies" included intellectuals and the wealthy. People were also detained "just because of false information," according to the government commission investigating the camps.

The first time Nikola Stoyanov was picked up, he was held for only 11 months. During that time he was beaten but not charged, and he came home in relatively good health. For Stoyanov and his three children, the tragedy of that arrest was in what it did to his wife.

Elena Valinova Stoyanova was 34 years old in 1944. A photograph at the time shows her as an attractive, dark-haired, aristocratic-looking woman with large brown eyes. Angry that police could take her husband away without explanation, she tried to do something about it.

"My mother put on her best dress and went to the militia station, which was near our house. She went at 5 in the afternoon and came home at 1 in the morning," Margarita Stoyanova recalled.

"She came into our house with a ripped dress and she was bleeding. She took off all her clothes, put them in the stove and burned them. Then she took a bath. She embraced us children and took us to bed with her. But she didn't sleep. I tried several times to get her to say what happened, but she said nothing . . . . She was raped at that place.

"The next day my mother went to visit her brother. She tried to jump out of a third-floor window of his apartment, but my uncle caught her by the coat. Afterward, she tried many times to kill herself. She cut her wrists, even her throat."

Except for two months in a mental hospital, the mother, now 80, has lived ever since with her daughter. Stoyanova, who has never married, described her mother as angry, fearful and helpless.

"In the case of my mother, for 45 years she has done nothing. We couldn't sleep for years because she was throwing things, smashing things at night. Sometimes she escaped from the house and went to the front of the militia building. She shouted, 'Where is my husband? What happened? I want my husband back.' "

Stoyanova's father was home for about 18 months -- during which time he could not find work -- before he went to the neighborhood Communist committee chairman to complain that his family had no food. That night at 1 a.m., Stoyanova recalled, 13 armed men broke into their house and took her father away.

"My father did not say anything. He just cried," she said.

The daughter said her father was moved from one prison or labor camp to another for the next three years. The family had heard that he had been beaten and hospitalized. On Dec. 9, 1947, he wrote them a letter. Part of it says:

"When you write me, you must be very careful and you must not mention that you know I have been in the hospital. Because it is very dangerous and the prison authorities must not know."

Two years later, Stoyanova, then 19, traveled with her uncle to a labor camp south of Sofia near the town of Bobovdol. Her father worked there.

"I saw him for about 10 minutes. I couldn't even recognize my father. He was a skeleton. It was the winter and he was dressed only in a T-shirt and torn pants. He told me not to embrace him because he was full of lice.

"I wanted to give my father the coat I was wearing, but the brute {a guard} beside me would not allow it. He slapped my hands. I asked my father, 'What are you doing here?' And the only thing he said was, 'I am innocent. I don't know why I am here. I hope to come home someday.' "

In 1950, the government sent Nikola Stoyanov's clothes to his family. There was no word about him.

Shortly after the commission report on "crimes done by the authorities" was released in April, several government officials singled out in it for their "exceptional cruelty" and "sadistic inclinations" were arrested. A Bulgarian court, however, has ordered their release from jail, and many are under house arrest. No trial date has been set.

The reform Communist leaders, all of whom held senior positions in the Zhivkov government, have tried to use public disclosure and symbolism to cleanse themselves of responsibility for the camps.

Petar Mladenov, a former foreign minister and now president, and Andrei Lukanov, a former minister of foreign trade and now prime minister, traveled recently to the city of Lovech, the site of one large camp, to place a plaque commemorating those who died.

Mladenov and Lukanov, respectively, enjoy the support of 72 and 69 percent of the Bulgarian public, according to polls this month.

Margarita Stoyanova, whose mother still howls and throws things during the night, is not among those who plan to vote for the reform Communists.

"I am not looking for revenge. That will only provoke more violence. But Zhivkov and those directly responsible should be tried and executed. Everything should be done in a proper way," she said. "As for Mladenov and Lukanov and the other Communists who worked with Zhivkov . . . I can't say exactly what should happen to them."