Documents declassified decades later reveal the CIA was aware of “Operation Condor” four months before the assassination.

A US ambassador in Paraguay knew of the Chilean agents trying to get visas to come to the United States. He denied their visas, but they entered the US anyway. According to an FBI informant, the agents recruited right-wing Cuban exiles in south Florida to assist with the killings. One of the DINA agents was American expatriate Michael Townly.

“Michael Townly, who is an American citizen, designed the plot, made the bomb, recruited the Cuban exiles and is now living in Kansas, he calls himself a developer,” said Landau who also co-wrote the book ‘Assassination on Embassy Row’ with journalist John Dinges.

None of the killers served more than a decade in prison. Most of them now live in Miami.

So what happened? Why were key perpetrators acquitted of the murders? Why were plea bargains accepted for the murder of an American citizen and high profile diplomat?

“There is some hidden history that needs to be uncovered before we know the full role. What we know is Bush, as head of the CIA, was pressed to release documents of Operation Condor to the Department of Justice for the investigation. The CIA was very reluctant to release those documents and to reveal its contacts with the secret police,” said Kornbluh.

During his short time in Washington DC Letelier became a member of the Institute for Policy Studies. It is where he met Moffitt and many of the people who came out for the 34th year in a row for a memorial service. The event was held by IPS to honor the legacy of their slain colleagues.

Letelier’s nephew, Rodrigo Leiva spoke on behalf of his family.

"This remains an open sore; it remains a task that has been undone. And it remains at least for my mother, a quest, a promise she made to her parents to fulfill to bring everyone to justice," he said.

RT asked the Chilean Ambassador to the U.S. "Has the current Chilean government condemned Pinochet's involvement in this assassination?"

Chilean Ambassador Arturo Fermandois responded “The Chilean government has been very clear on condemning any human rights violation. The Chilean government supporting the investigations for the rule of law."

A scene of flowers, music and memories. However none of it answers the lingering questions or delayed justice still hovering over one of the most infamous assassinations carried out in the heart of Washington, DC.

“I think that the CIA, at the moment of the assassination, probably said ‘holy cow’, we knew there was something going on but we didn’t know it was this assassination. They probably kicked themselves; they’ve been covering up that advanced knowledge since. But I don’t believe they had a role in it,” said Dinges.

He explained however that more importantly the US created the government that carried out the assassination and it continued to support that government for a decade afterwards.