In a public appeal earlier this month, former President Muhammad Khatami called on “the authorities” to end the house arrest of former presidential candidates Mir Hussein Mousavi and Mehdi Karorubi before President-elect Hassan Rouhani takes office in August.

Even from the point of view of the regime’s interests, Khatami’s appeal makes sense. If the new president starts work while the dissident leaders are still under house arrest, Rouhani would not be able to claim that his election had helped ease tension in the country. If, on the other hand, the two men are set free after Rouhani is sworn in, the impression would be that they were locked up by outgoing President Mahmoud Ahmadinejad.

However, Ahmadinejad—now re-touching his image—has stated that he had nothing to do with their detention and the decision to hold the dissidents under house arrest.

The trouble is that no one quite knows who ordered the arrests. The “Supreme Guide” Ali Khamenei’s office insists that he does not intervene in the judiciary. The head of the judiciary, Sadeq Larijani, another mullah, says that his outfit is not involved in arresting people.

So, if we don’t know who ordered the arrests, whom do we invite to order the release?

The problem gets more complicated as lawyers for Mousavi and Karroubi insist that neither has been charged with anything, let alone a specific “crime” punishable by house arrest. The same applies to Mousavi’s wife, Zahra Rahnavard, who is also under house arrest.

Could we consider Mousavi, Karroubi and Rahnavard to be political prisoners?

Here, too, things are not that simple.

Believe it or not, the legal system of the Khomeinist republic makes no provision for “political crimes.”

“We have no definition for a political crime,” says Allahyar Malekshahi, chairman of the Legal and Judicial Commission of the Islamic Majlis, Iran’s parliament. “We have now set up a three-man committee to provide a definition and suggest it for legislation,” he said.

All that may sound surprising when we remember that over 4,000 people are currently in prison or under house arrest for alleged but undefined “political crimes.” According to estimates by human rights organizations, over the past 35 years half a million Iranians have spent varying lengths of time—from a few hours to decades—in prison for the same undefined “crimes.” And that is not taking into account the countless people who have been executed.

Malekshahi admits that many people are in prison for theoretically legal political activities because the system does not make it clear what constitute political crime.

Malekshahi also promises that a draft bill to address the anomaly will be presented to the Majlis within the next year or so.

The regime has always pretended that citizens enjoy full political freedom. Thus it has imprisoned and/or executed real or imagined opponents on charges that do exist in the Khomeinist legal system. These include “waging war on Allah,” “spreading corruption on earth,” and, of course, espionage and high treason. In most cases, such “crimes” are punishable by death.

It is clear that none of those charges could be leveled against Mousavi, Karroubi and Rahnavard. If it had been possible to bring such charges against the three, the regime would and should have done so during the past four years. The three have been deprived of their basic freedoms for four years for no legal reason.

So, what is their status? The best answer is that they are hostages. But this begs another question: who are the hostage-takers?

We cannot say for sure because none of the official organs of the regime admits responsibility.

This shying away is understandable, particularly as seizing and holding hostages is a major crime under the Iranian Penal Code punishable by 15 years imprisonment and, in cases where it leads to the loss of life, the death sentence.

In his interview with a Tehran daily, Malekshahi skirted the question by insisting that his committee was not “dealing with individual cases.”

That is fair enough. However, the committee cannot ignore the Mousavi-Karroubi-Rahnavard case, at least as a point of reference. For here, we have three senior officials of the regime, held hostage without being charged with any crime. All that they did was to reject the results of the 2009 presidential election. But neither the Khomeinist constitution nor the Iranian Penal Code—which incidentally is based on the Napoleonic Code—considers this to be a crime, let alone one punishable by being held hostage.

Should Mousavi, Karroubi, and Rahnavard remain captive, without being charged and tried, let alone sentenced, until a new law determines what a “political crime” is?

Even if such a law is enacted it could not apply retroactively. In other words, the trio cannot be charged for a “crime’ defined five years after they supposedly committed it.

The Islamic Republic has invented a new legal system in which people are punished first and charged afterwards.

Throwing people in prison is easy; releasing them complicated.

Let us return to Khatami’s appeal. One might have hoped that the former president would have extended his appeal to all those currently under arrest due to their rejection of the 2009 presidential election results.

Fixing the focus on the trio of Mousavi-Karroubi-Rahnavard may be designed to make it easier for the powers-that-be to terminate the hostage-holding drama.

However, there is no guarantee that, once freed, Mousavi and his two fellow-hostages would not seek to bring a lawsuit against those who robbed them of their freedom for so long. And that could open a whole new can of worms, one that could shift attention away from Rouhani as he starts his presidency.

Thus, releasing Mousavi, Karroubi and Rahnavard requires a political deal at the summit of the Khomeinist regime. Could Rouhani play a role, behind the scenes, to shape such a deal? Might his “key” open the gates behind which so many people are captive without being charged with any crime?