From 2007 to at least 2010, there was a flight from Caracas, Venezuela to Tehran, Iran that made a stop in Damascus, Syria.

Hugo Chavez and Mahmoud Ahmadinejad reportedly called it 'Aeroterror.' Only government officials with a special clearance were permitted to fly on it, and there were often very few passengers.

Instead, according to US government testimony and a report by Brazilian paper Veja, the plane was laden with drugs, weapons, and cash.

Since the mysterious death of Argentine prosecutor Alberto Nisman in January, Iran's presence in South America has come into focus. Nisman died the day before he planned to testify that the Argentine government had covered up Iran's involvement in a 1994 Buenos Aires terrorist attack. He had spent about a decade investigating Iran and Hezbollah's growing presence in the Western hemisphere.

High-level Venezuelan defectors then started talking to Veja journalist Leonardo Coutinho. They told Veja that Aeroterror came to be a biweekly flight that carried drugs and cash to finance Iran's activities in South America, and that it would stop in Damascus to pick up fake passports and other documents to ensure that Iran's agents could move freely once they arrived in Caracas.

"Not only is [the Veja report] credible, but it underscores the allegations prosecutor Nisman put forth about Iran's longstanding desire to have Argentina restart nuclear cooperation with Iran," Toby Dershowitz of the Foundation for Defense of Democracies told Business Insider.

Testimony from diplomats and Nisman over the years corroborates Veja's work.

"The Venezuelan state-owned airline, Conviasa, operates regular service from Caracas to Damascus and Tehran – providing Iran, Hezbollah, and associated narco-traffickers a surreptitious means to move personnel, weapons, contraband and other materiel," former Assistant Secretary of State for the Western Hemisphere Roger F. Noriega said in Senate testimony back in 2012.

The path of a direct flight from Caracas to Tehran. Google Maps

Noriega continued: "Mr. Chairman, our project has shared substantial information about these aforementioned threats with U.S. government officials — either directly or through Members of Congress. Quite frankly, too often the attitude we have encountered has been one of skepticism or indifference."

What Nisman was about to report before he died — an exhaustive report on Iranian orchestration of the 1994 Buenos Aires bombing that followed a 502 page report he published back in 2013 — also corroborates the Aeroterror claims.

Late Argentine prosecutor Alberto Nisman pauses during a meeting with journalists May 29, 2013. Marcos Brindicci/Reuters Before that, Nisman published a report on the same subjects that he took to Interpol in 2007 — Iranian officials threatened to arrest Nisman after it was presented.

Reports indicate that Chavez and Ahmadinejad planned Aeroterror at a meeting Caracas back in 2007, during which Ahmadinejad also asked Chavez to help him get Argentina to help Iran with its nuclear program. Since then, Iran has only strengthened its ties to South America.

"The DOJ and other USG agencies should be concerned about who killed a prosecutor with whom it had an important relationship and whether it was aimed at silencing him and his work implicating Iran," Dershowitz said. "Nisman's work was akin to a canary in a coal mine, and his suspicious death is a matter I hope the next attorney general and others will pursue impartially even if it comes at an inconvenient time as the P5+1 negotiate a nuclear deal with Iran."

Nisman tried to track the network of Mohsen Rabbani, who he believed led Iran's cell in Latin America and was an architect of the 1994 bombing.

Iranian operatives eventually reached Washington DC in 2011, when Tehran recruited a man to attempt the assassination of a Saudi ambassador at an upscale Georgetown restaurant.

Noriega, the former Assistant Secretary of State for Western Hemisphere affairs, mentioned the threat of this Iranian network in the West during his 2012 Senate testimony:

U.S. Assistant Secretary of State for Western Hemisphere affairs Roger F. Noriega in 2004. REUTERS/Luis Galdamez LG/HB "Chávez’s petro-diplomacy has paved the way for Ahmadinejad to cultivate partnerships with anti-U.S. regimes in Cuba, Ecuador, Bolivia, Nicaragua et al. Today, a shadowy network of commercial and industrial enterprises in several countries affords Iran a physical presence in relatively close proximity to the United States," he said.

"Iran is well- positioned to use its relationships with these countries to pose a direct threat to U.S. territory, strategic waterways and American allies."

Significantly, the status of this network — and those shady flights to and from Tehran — is unclear to this day.