For two decades, Estela de Carlotto has kept in a folder the name of the man she believes killed her daughter Laura, who vanished in 1977, at the height of the Argentine military government's crackdown against political dissidents, known as the "dirty war."

Until recently, though, she saw little point in pursuing the case. The man was a low-ranking military official, legally exempt from punishment for crimes committed in uniform. Instead of brooding fruitlessly, Carlotto banished him to the file on her office shelf.

But last week, Argentina's Supreme Court ruled that laws passed in the 1980s to protect such officers were unconstitutional. That meant Carlotto and other relatives of the thousands of people believed tortured and killed during a seven-year dictatorship were finally free to seek criminal and civil cases against the officers they held responsible.

Soon after she heard the news, Carlotto reached for the long-untouched folder.

"I'm going to start looking into this man, to find out where he is, and to start compiling all of the information that I can about him," said Carlotto, 75, a widow with white curls and a composed, determined air. "If I can prove he killed my daughter -- that he pulled the trigger -- he will finally go to jail."

The Supreme Court decision is the latest in a series of steps Argentina has recently taken to confront its bloody past. At least 10,000 Argentines disappeared during the dictatorship, which means that further investigations into past human rights abuses could affect a wide swath of the population on a deeply personal level.

While human rights groups have praised the court decision, critics argue that the country is foolishly picking at wounds that had started to heal. And while some victims' relatives say they are eager to take advantage of the ruling, others are not sure they want to endure the legal and emotional ordeal of digging into long-ago crimes.

In the mid-1980s, the civilian government led by President Raul Alfonsin moved cautiously on human rights issues to avert a possible military coup. Prosecutions were confined to leaders and senior officers of the 1976-83 military dictatorship, while lower-ranking officers were given immunity. After that, a succession of civilian rulers maintained that it was better to turn toward the future than dwell on the past.

"Something happened after they passed the protections. Maybe some part of the population thought justice was hopeless after that point," said Jose Miguel Vivanco, director of the Americas division of Human Rights Watch, speaking from Washington. "Only in recent years have they realized it's possible again."

It was not until President Nestor Kirchner took office in 2003 that officials began pushing to hold the military more accountable. Kirchner has fired several commanders. He also removed a Catholic bishop assigned to the armed forces for declaring that the health minister should be "thrown into the sea" -- a fate many long-missing dissidents are believed to have suffered -- for suggesting abortion should be legalized.

Moreover, in the past two years, four of the Supreme Court's nine justices have been impeached or have resigned under threat of impeachment. Last week, the four new justices appointed by Kirchner voted in favor of reversing the immunity laws. The vote was 7 to 1 with one abstention.

"The laws of immunity are not applicable to crimes against humanity," Justice Antonio Boggiano said in explaining his vote. "If they were applied, they would be unconstitutional."

Laura Carlotto, a 22-year-old political activist, was 21/2 months pregnant when she disappeared on Nov. 26, 1977. Ten months later, her family got a call from military officials who said she had been killed during a shootout between the army and members of a radical political group.

"They lied, saying that she'd never been kidnapped and that she was fully armed when she was killed," said Estella de Carlotto, who eventually received her daughter's body. "Forensic analysis showed that she had been shot at a distance of 30 centimeters, lying on her back, on the floor. One of her arms had been broken, probably because she tried to resist."

Several witnesses later said they had seen Laura in a military detention center. They said that she gave birth there to a boy named Guido on June 26, 1978, and that a high-ranking officer claimed the baby as his own. In 1985, during a government investigation of military crimes, a former soldier testified that he knew who had shot and killed Laura. Carlotto obtained a copy of the testimony but took no action.

"It was never my intention to pursue him myself. I want the justice system to pursue him," she said. "People sometimes ask me what I would do if I ever met him face to face . . . . I say I would feel deep pity for him, and enormous contempt."

Carlotto did make efforts to locate Guido, who would be 27. She joined an advocacy group dedicated to finding an estimated 500 children of those known as "the disappeared" who were believed to have been illegally adopted by military families. Although she never tracked down her grandson, she helped 80 children of victims discover the truth about their adoptive parents and steered them toward their biological families.

Recently, she has noticed that Argentines are increasingly willing to delve into the past, especially young people whose parents disappeared years ago. Despite the psychological upheaval, she said, almost every day someone walks into her office seeking to investigate personal history.

"Everyone has his own time, but it seems that many of the children get more courage to investigate this as they get older," Carlotto said. "The doubts they might have grow into certainties. They start to say, 'I need to know who I really am.' "

As he grew up, Matias Olivera always knew his father had been kidnapped at a train station on his way to work. But the crime occurred when Matias was an infant, and he had a happy childhood with a mother and stepfather who loved him. He never told his friends about his father's fate, and he avoided advocacy groups for relatives of the disappeared.

But two years ago, he said, an indefinable urge prompted him to type his father's name into the Google Internet search engine. Links filled the screen. He followed them to Web sites for human rights groups, biographies of the disappeared and a history of his father's labor union. He created a folder to file the information he collected.

"I don't know why, but it seems like a lot of young people had decided to put a wall between themselves and this subject," said Olivera, 27, who works for a telecommunications company. "But in the last couple of years, everything seems to have started over. A lot of people my age are going through the same process that I am."

The recent Supreme Court ruling filled Olivera with contradictory feelings. He said he had learned the location where his father was detained and the name of the officer who ordered it. With more effort, he said, he could probably create a detailed picture of his father's last days and add that to the folder.

For now, however, Olivera plans to leave the case alone. The justice system might finally be ready for him to dig deeper into his father's fate, but he's still not sure he's ready to handle the entire, grim truth.

"I don't really want to know how he was tortured and killed, and I don't care about getting revenge," Olivera said, pausing to control a surge of emotion. "But when things like this happen, it reminds you how much of your life is connected to that time. You start to see that even though you might have been safe during your own life, what happened back then can ruin your life in many ways."

Estela de Carlotto, front left, and other relatives of the missing celebrated the June 14 Supreme Court decision.