Forty years ago today, Argentina experienced a military coup that threw out then-president Isabel Perón. What followed was seven years of military dictatorship, where tens of thousands of people “disappeared.”

But they didn’t simply disappear – they were tortured and killed by the militia. The military claimed these people were from violent guerrilla groups, threatening Argentina’s democracy, but many were college students, professors, priests, and social workers – anyone who was deemed a threat or spoke out against the Argentine government, a dictatorship that lasted from 1976 to 1983. Some say human rights violations had been taking place even before the military officially took power.

The role the U.S. played in Argentina’s so-called Dirty War is still a little unclear. Many Americans don’t know about the country’s involvement in Argentina’s Dirty War, but Argentines have some lingering anti-American sentiment because they feel the U.S. is responsible for some of the crimes committed during that time.

President Barack Obama, who is in Argentina today, has pledged to declassify U.S. military and intelligence records surrounding the events.

Mark Jones, a fellow in political science at the Baker Institute at Rice University, says Argentines believe the U.S. was, at the very least, complicit in murders, if not directly responsible.

“Declassifying these archives will go a long way towards clarifying what the actual U.S. role was,” Jones says. “It’s probably going to look bad for the United States in the short term, but in the long run it’ll be beneficial because it’ll clear the slate.”

Jones says maybe we’ll see that the American government wasn’t as involved as Argentines’ think.

“We’re going to see … how much the U.S. government knew about what was going on – particularly the kidnappings, the tortures, the murders of civilians throughout Argentina,” Jones says.

Jones says releasing classified documents will be a show of honesty, and a step toward making amends.

“We could see some new prosecutions,” he says, “if individuals who hadn’t been previously charged with crimes against humanity or other crimes are revealed in these documents. That could be the proof that Argentine prosecutors need.”

After 12 years of worsening relations with Argentina, President Obama is spreading the message to American corporations that Argentina is open for business.

“(Argentina’s President Mauricio Macri) has a fundamental goal of improving Argentina’s economic conditions, and that can only be done with international and foreign investment – especially investment from the United States,” Jones says.