Earlier this month, the U.S. Department of Treasury opened investigations into former government officials who have been paid speaking fees by the Mojahedin-e-Khalq, or MEK, an Iranian resistance group officially listed as a terrorist organization.

The subpoenaing of former Pennsylvania Governor Ed Rendell, ex-FBI Director Louis Freeh and retired Gen. Hugh Shelton has cast an harsh light on other U.S. officials, including former New York City Mayor Rudi Giuliani and former Vermont Governor Howard Dean, as well as the organization they publicly support.

They (MEK) are still on the terrorist list. The laws still apply. It is illegal in every sense of the word to finance them right now, said Trita Parsi, founder of the National Iranian American Council, a non-partisan community organization based in Washington.

The actual sum being paid to these officials is vague, but judging by the fees handed to certain individuals, the total could be in the millions. For example, Rendell was allegedly paid $150,000 for seven or eight speeches, according to reports. Giuliani, who spoke in at a conference in Paris, France on behalf of Iranian resistance figures alongside 18 other international guests, has been known to charge up to $100,000 for a single appearance and sometimes demands private jets to charter him to appearances.

Other former U.S. officials told the New York Times that the American supporters of MEK received between $15,000 and $30,000 per speech, yet others said they made appearances for free.

Where does an organization based in an Iraqi refugee camp for the last 25 years get so much money? While MEK has organized rallies and campaigns to have it delisted as a terrorist group in the past, it has never, by all accounts, spent the amount of money it has over the past year.

Currently, there are rumors that the Israeli secret service is paying MEK to carry out assassinations of Iranian nuclear scientists. Three unnamed U.S. government officials told NBC news last month that Mossad had trained and paid MEK militants to conduct a spate of car bombings against targets like Mostafa Ahmadi Roshan, a university chemistry professor who doubled as a director of Iran's Natanz uranium-enrichment facility, who was killed in Tehran in January after two assailants on a motorcycle attached a magnetic bomb to his Peugeot 405.

MEK called the allegations outright false, but Israel has neither denied nor confirmed its own involvement in the attack.

If the NBC report is true, Israel would not be the first government to pay for MEK's military expertise; from 1980 until the invasion of Iraq in 2003, MEK was funded by Saddam Hussein. Following the adage the enemy of my enemy is my friend, MEK joined Hussein during the Iran-Iraq War and fought viciously against the Ayatollah's forces. MEK made Camp Ashraf, which is about 55 miles north of Baghdad, its permanent headquarters in 1986.

Some estimate that Hussein was paying as much as $30 million a month for at least 10 months -- some of it allegedly run-off from the UN's failed Oil-for-Food program -- for MEK's services, which included strikes against Kurdish and Shia rebels in Iraq.

Additionally, during the Iran-Iraq War, MEK leader Masoud Rajavi -- whose wife Maryam Rajavi currently runs the National Council of Resistance of Iran, or NCRI, MEK's political arm -- allegedly took control of all of his members' assets, possessions and even their passports so they couldn't leave Camp Ashraf.

Between 1978, when I became MEK's supporter, till 1996 when I escaped, through use of different techniques of mind manipulation I was forced to give them whatever they asked me, explained Masoud Banisadr, MEK's former U.S. spokesperson and the second cousin of Abolhassan Banisadr, the first president of the Islamic Republic.

First any capital or material things we had; then any love, attachments or relation we had with our country, our family and friends in Iran; then when they asked all members to divorce their spouses, I lost the love of my life, my dear wife and could not see my children for almost six years; I lost part of my health, and many times were on the edge of dying for them.

In 2003, before the European Union took MEK off of its terror watch list, Maryam Rajavi and some 160 other Mujahedin were arrested by counter-terrorism police in a small town outside Paris. Authorities confiscated around $8 million in cash, which Trita Parsi believes was some of the last remaining funds of Saddam Hussein. All of the suspects were quickly released and the case was eventually dropped.

Follow the Money

MEK was put on the State Department's list of Foreign Terrorist Organizations in 1997. MEK supporters suggest this was a failed political move by the Clinton administration to soften relations with Tehran. Regardless, the organization says it is now a peaceful and democratic resistance movement, one allied with the U.S in its distrust of the current Iranian regime and Iran's nuclear program. A slew of American officials, including Freeh, FBI Director at the time the terror list designation was made, and a number of military officers of the highest rank, have come to the support of MEK and lobbied for its removal from the terrorist list.

A 2004 FBI investigation uncovered a glut of shady fund-raising operations. According to the report, the voracity of which has been called into question, money raised by the Los Angeles and Washington D.C. cells was transferred overseas through a complex international money laundering operation that uses accounts in Turkey, Germany, France, Belgium, Norway, Sweden, Jordan and the United Arab Emirates.

At one point, MEK was also operating charities called the Committee for Human Rights and Iran Aid, which claimed to raise money for Iranian refugees persecuted by the Islamic regime, but was later revealed to be a front for MEK's military arm, the National Liberation Army.

All of this could account for some of MEK's resources but would be unlikely to cover the exorbitant speaker fees recently doled out.

Moreover, MEK supporters would claim that if true, these practices were done during a previous incarnation of the group, the middle ground between being a fully-militant organization and a refugee group under U.S. military protection in Iraq.

Almost all of the former U.S. officials who support delisting were not actually paid by MEK, but by Iranian-American cultural organizations like the Iranian American Community of North Texas and the Iranian American Cultural Association of Missouri. This network of non-profits could be the best way to track MEK's funding. According to experts, money from benefactors and pledge drives in Europe is sent to individuals in the United States, then onto front groups and finally given to American politicians. It's complicated, but according to federal law, it's still illegal.

It's much easier to move around money in Europe because MEK is no longer on the watch list, said Parsi.

None of this may matter soon. MEK has filed a federal suit that would force the State Department, which says it continually evaluates the terrorist organization list anyway, to officially review the organization's status within 30 days.

Secretary of State Hillary Clinton also said that a successful transfer from Camp Ashraf to former U.S. military base Camp Liberty, which is currently underway, will help speed up any potential delisting. If that happens, former politicians like Giuliani, ex-Homeland Security Secretary Tom Ridge and former U.N. ambassador John Bolton will continue to advocate for the MEK despite criticism and possible legal ramifications.