Hundreds of Iranians have taken to social media to vent their frustration about the opaque nature and outcome of the judicial proceedings against the businessman, who says he was backed by powerful officials during the term of hardline former President Mahmoud Ahmadinejad.
Zanjani has said he helped Iran circumvent sanctions by selling its oil abroad. He was arrested in 2013 and detained in Tehran, accused by the judiciary of pocketing more than $2.7 billion for oil sold on behalf of the Ahmadinejad government, months after moderate President Hassan Rouhani won power campaigning against corruption in government.
Zanjani, who is in prison, has denied withholding oil revenues. "As soon as the government changed I was portrayed as a thief," he said in court, according to the Fars News agency. He plans to appeal his death sentence, which was handed down this month.
Reuters was unable to contact Ahmadinejad for comment.
The case has highlighted the complexities of Iran's system of clerical and republican rule where power is wielded by both elected and unelected officials. But much remains unclear, including any involvement of government figures in Zanjani's financial transactions, due to the opaque nature of the Iranian political and judicial systems.
Rouhani, who says he wants to wipe out the corruption that spread during his predecessor's tenure, has publicly criticised the handling of the case. The president has questioned who enabled Zanjani to carry out deals involving huge sums of money and whether that money can be recovered if he is executed
"Who protected him and created a space for him to do such things?" Rouhani said at a gathering during a visit to the city of Yazd last week. "What the people want is to know how and with who's permission this individual was able to sell oil and where has all of this money gone now?"
"Execution isn't going to solve any problem," he added.
Rouhani has little sway among the hardliners who dominate the judiciary, which is independent of government. The president, whose power is eclipsed by that of Supreme Leader Ayatollah Ali Khamenei, has clashed with judicial authorities on several occasions since winning power, on issues ranging from public music concerts to the arrests of journalists.
He cannot revoke a death sentence, a power held only by the supreme leader and the head of the judiciary, according to Hadi Ghaemi, executive director of the International Campaign for Human Rights in Iran.
Two lawmakers on a parliamentary committee separately investigating the case to identify any wrongdoing in government and recover the oil revenue, said an execution would do little to tackle corruption.
They said it would allow officials who backed him to escape justice - though they did not identify any such figures or explicitly accuse these officials or the judiciary of trying to silence Zanjani.
"Executing the accused will allow the hands behind the scene, who were even more responsible for this case than the accused, to be forgotten," Hussein Dehdashti, an independent lawmaker, said on March 6 after the sentence was announced, according to the Islamic Consultative Assembly News Agency.
Amir Abbas Soltani, another independent lawmaker on the committee, said: "The government officials who were corrupt and profiteering are still being protected and have not been confronted."
"They haven't even been questioned in court," he said in an interview with the Iranian Labour News Agency last week. "By executing one or two people accused in this case and ignoring the main people responsible, the problem of this case and economic corruption in the country will not be solved."
The committee was set up at the time of Zanjani's arrest. Soltani told Reuters on Tuesday that the aim of the 10-strong panel was to "identify and reveal the people who were involved in the profiteering, fraud and corruption with him and protected him", as well as to secure the return of the money.
Asked what legal authority it had, he added: "They can legally pursue this matter until they achieve a result." He did not elaborate.
It is not clear if the committee has the power - constitutionally or in practice - to punish any officials who might have backed Zanjani's activities.
Two other lawmakers who are not on the committee, Gholamali Jaafarzadeh Imanabadi and Mohammad Ali Esfanani, have also publicly criticised the death sentence and said it would prevent officials who supported him from being revealed - without giving any names.
Many ordinary Iranians have little affection for Zanjani, one of Iran's richest men who amassed a fortune as they toiled to make ends meet under the hammer of sanctions. Nevertheless hundreds of Facebook, Twitter and Telegram users expressed their anger about the secrecy surrounding one of the biggest financial corruption cases in Iran's history and the sentence handed down.
Over the course of more than 20 court sessions, media coverage has been mostly limited to short pieces of video footage, stills and excerpts of brief exchanges between Zanjani and the head judge.
"Executing him will not help in combating corruption but will have the opposite effect," said a Facebook user named Mamad.
A Twitter user with the tag "Tiffany" posted in Farsi: "Your sick system isn't going to get better with these things. Nobody gets fooled by this kind of show anymore."
In court - decked in a striped blue uniform rather than his usual expensive suits - and in media interviews before his arrest, Zanjani described conducting a series of business deals via a complex network of companies to evade sanctions imposed by the West over Iran's nuclear programme.
The tycoon, who plans to appeal his sentence, boasted of his contracts and ties with businesses linked to the Revolutionary Guards, Iran's most powerful military and economic force.
He said that Rostam Qassemi, a former senior Guards commander who served as oil minister under Ahmadinejad, asked him to bypass sanctions and sell oil on behalf of the ministry. He has also said he has worked on deals with several other senior officials from the Ahmadinejad government, though it was not clear if they involved circumventing sanctions.
Reuters was unable to determine if Zanjani presented any evidence to support his allegations.
Repeated calls to a Revolutionary Guards media office for comment were not answered. Reuters was unable to contact Qassemi for comment.
Last October Qassemi, along with five other senior officials who served under Ahmadinejad and had allegedly had dealings with Zanjani, wrote a letter to the attorney general asking for any evidence of financial links between the businessman and any government official to be made public.
The letter appeared to be an attempt by the officials to dissociate themselves from any criminal activities described in the trial.
The judiciary has not disclosed any such ties between Zanjani and government officials or any charges against officials. The reasons are unclear.
According to Fars News, the other officials who signed the letter are: Seyed Shamseddin Husseini, former minister of economic affairs and finance; Ali Nikzad, former minister of housing and urban development; Mehdi Qazanfari, former minister of industry, mine and trade; Behrouz Moradi, former deputy for planning and strategic supervision; and Mahmoud Bahmani, former governor of the central bank.
Reuters was unable to contact the five men for comment.
Abbas Milani, the director of the Iranian Studies programme at Stanford University, said the planned execution was an attempt to prevent Zanjani from disclosing further information.
"It indicates the Sopranos style of politics in Iran and the Sopranos style of the economy in Iran," he added, referring to the TV show about the U.S. mafia.
Rouhani's election in 2013 and gains by moderates in both the parliament and Assembly of Experts polls two weeks ago were viewed by analysts as partly a reaction against the perceived corruption and mismanagement of the Ahmadinejad days.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)