There's an office in this grandiose and sprawling city of Buenos Aires that holds a somewhat macabre collection: over 700 human skeletons. They are presumed to be but a small fraction of the unidentified remains of the over 30,000 supposed "subversives" who the rightwing military government of the late 70s and early 80s tried to make disappear from the face of the earth.

"In our profession, we always arrive late in a way. We use whatever documentation was left by the military to find the bodies." Luis Fondebrider tells me, co-founder of the Argentine Forensic Anthropology Team (EAAF). "The most complicated part is getting DNA information from bones, but the latest advances in genetic testing has helped. Some of our more recent identifications are of skeletons we've had for 15 years."

For years the nonprofit team of bone hunters and forensic investigators, with offices in Buenos Aires, the western Argentine city of Córdoba, and New York, have been working with human rights activists and judicial authorities in Argentina and around the world on a project that should give war criminals everywhere pause – they help undisappear the disappeared. The team has identified victims of state terrorism in Argentina and elsewhere, providing key evidence that has led to convictions of a number of assassins who might have gotten away with it, if not for advances in modern forensic science.

Last week their work was once again vindicated when a very big fish was caught and charged with almost 50 cases of kidnapping, torture and murder. Thanks to the tireless work of human rights groups in Argentina over the years, justice had already caught up with former Argentine dictator Jorge Rafael Videla, who ruled from 1976 to 1981. He is due to stand trial in September for his role in a particularly twisted racket during the dictatorship – the kidnapping of babies of assassinated political opponents, which were then "gifted" to families sympathetic to the regime. The new murder charges, filed by federal judge Daniel Rafecas, are drawn directly from positive identifications that EAAF investigators made in the last two years, from skeletons exhumed from unmarked graves in 10 cemeteries in or around Buenos Aires.

"For us it means – I can't say happiness – but satisfaction," Fondebrider told me the day after the new charges were announced against Videla. The ex-dictator will now appear in court at the end of the month, for the first time in 25 years. (Videla was sentenced to life in prison in 1985, but was pardoned along with other military leaders in 1990). "In our part of the world perpetrators of state terrorism often aren't charged, or often there's not enough information to bring them to justice. So it's one of the few times that our work helps to break through that impunity."

There's an undeniable poetic justice at play. For years it was up to family members and human rights groups such as the Mothers of the Plaza de Mayo, Grandmothers of the Plaza de Mayo, and HIJOS to keep the memories alive of those who disappeared, against an official culture of impunity that pushed people to "stop dredging up the past". But the brutal charnel house that was Argentina in the late 70s and early 80s also led to the development of an organisation with a particularly sophisticated expertise in digging through mass graves – and using continued advances in forensics to reclaim the identities of those who were so meticulously extinguished during those years of blood and fire.

Some victims will likely never be found – one common form of disappearing kidnapped victims at the time was by drugging them and throwing them live in to the ocean. Luckily for forensic investigators, though, some of the perpetrators in the armed forces maintained at least some semblance of propriety.

"Many of the military men were Catholics," Mercedes Doretti tells me, an EAAF co-founder who works out of the New York office. "They believed that even subversives should receive a Christian sepulture."

The team's expertise is now increasingly in demand around the world as its members consult with human rights activists, prosecutors, and family members in countries where human rights crimes, disappearances and other forms of state terrorism are also finally being investigated (South Africa, Colombia, El Salvador, East Timor).

Doretti is working with investigators from the US and Mexico to study the cases of unidentified murder victims along the vast border. Excavations continue apace in the Argentine provinces of Córdoba, Tucuman and Mendoza. And the organisation continues to grow a massive genetic database containing DNA information of family members of the disappeared to help identify future remains, or to confirm the identities of kidnapped and misappropriated children. And at least one dictator will have to stand trial and account for the lives extinguished under his rule.

Political violence is nothing new, of course, and sadly we'll still likely be in need of the EAAF's specialised expertise well in to the future. But it's heartening to know that at least the science continues to catch up with the human heart's demands for justice.

• This article was amended on 17 May