Buenos Aires, Argentina (CNN) -- Laura Feldman was kidnapped by the Argentine military on February 18, 1978. The 18-year-old was never seen by her family again, a victim of the ruthless regime that ruled Argentina from 1976 to 1983. For 31 years, her sister Ana searched for answers -- and her remains.

"Laura was politically active. She was young and had her ideals. But she didn't deserve to die," says Ana, 51.

In 2004, bones believed to be Laura's were found in a mass grave in a cemetery outside Buenos Aires. After a series of genetic tests confirmed her identity, Ana finally received her sister's bones in April 2009.

"I can now speak in the past tense: my sister was executed," says Ana. "And now that I have her remains, I can mourn her -- something her murderers tried to deny me," she says.

Ana has her sister's remains today because of the efforts of the Argentine Forensic Anthropology Team -- known by its Spanish acronym as EAAF -- a non-profit, NGO based in Buenos Aires that uses science to solve the mysteries of Argentina's "Dirty War," a period during which at least 13,000, and perhaps as many as 30,000 people, were "disappeared."

The "Dirty War" is still very much alive in Argentines' collective conscience. Immunity laws granted to former military leaders were overturned in recent years, and now many are standing trial for human rights violations, including the country's last military dictator, former Gen. Reynaldo Bignone, 81, who went on trial this month along with five others on torture charges.

Since 1984, the EAAF team has used forensic anthropology and other disciplines like archaeology, ballistics and radiology to locate, identify and ultimately, reunite, family members with the skeletal remains of their loved ones. As their skills and experience have grown, so has demand for them. The team now travels the globe regularly, visiting other countries where human rights violations and mass murder have occurred, like Sudan, Haiti, Ethiopia and El Salvador.

"You are dealing with violence, with human rights, with relatives that lost their loved ones. In a perfect world, we wouldn't need this job, but we are proud of what we do," says Mariana Segura, 28, a team member since 2001 who has also worked in Paraguay, Bolivia and East Timor.

For the families of Argentina's disappeared, the work the EAAF team does is vital in bridging the past with the present.

"The team is made up of all young people, most of whom did not live through the era of state terrorism here, but they have taken on this investigative task as a moral obligation," says Sara Cobacho, a human rights activist who lost six family members to the dictatorship, including two sons, neither of whom have ever been found.

During a recent exhumation at a cemetery in the Buenos Aires suburb of Merlo, the EAAF team opened two plots where they believed victims may have been dumped into unmarked graves. After carefully separating dirt from human remains, and meticulously marking, labeling and photographing the condition of the graves, the skeletons were removed, wrapped in paper, and then boxed up for analysis in the EAAF laboratory.

One of the skeletons had a two-centimeter bullet-sized hole in its skull, likely from a point-blank gunshot, a bleak reminder, the team says, of the brutality that took place in Argentina not long ago. "You learn the history of the disappeared person, and their family, and of course, you get very close to them. It can be hard," says Segura.

A recent EAAF campaign -- funded in part by a grant from the U.S. Congress -- yielded more than five-thousand blood samples from relatives of missing dictatorship victims. The samples came from throughout Argentina and Latin America, as well as from as far away as Spain and Sweden.

The blood samples were then sent to a forensic laboratory in the United States, where they were compared with bones that the EAAF team had already collected. The results surpassed expectations: 42 missing people were positively identified, and their remains have since been returned to their families.

More identifications are expected soon. Closure like that is exactly what EAAF team members strive for, but they say just arriving to that point can be physically and emotionally grueling.

"I try to put mind blank and do my job," say EAAF member Analia Simonetto, 29. "It's the best thing I can do for them and the families that are searching for them and want some explanation of what happened to their beloved ones."

Now that the forensic secrets held in blood and bones have reunited her with her sister's remains, Ana Feldman is looking forward to the next step in closing this painful chapter in her life: the trial of the former officers suspected of killing Laura, which will begin in Buenos Aires on December 15th.

"The EAAF team is deeply committed, and their amazing work should be commended," she says.