For the past two weeks, Iran has been embroiled in mass protests against the Iranian regime. The streets are filled with courageous women and young Iranians who have had enough of the regime's medieval barbarism, massacres, and systematic discrimination and oppression in virtually every domain of human life.

The protests that have morphed into nationwide uprising, spreading like wildfire to 162 cities by the end of September. At least 240 protesters, many in their 20s and 30s, have been shot to death and 12,000 arrested.

Nevertheless, the protesters have remained defiant. In their cries, I can sense the spirit of thousands from my generation who were massacred by the genocidal theocracy in 1988.

This regime must be held to account for the manifold of crimes it has committed, including the 1988 massacre, lest it continues to murder innocent young Iranians currently demanding their basic human rights on Iranian streets.

This is why a group of Iranian expatriates filed suit against President Ebrahim Raisi in U.S. district court. Raisi was instrumental in issuing orders to execute at least 30,000 political prisoners in 1988.

I am one of the 16 plaintiffs in the case.

The fact that Raisi was allowed to speak at the U.N. last week, even as protesters were being butchered across Iran, was abhorrent and shameful.

Raisi was involved in what may be the greatest unresolved crime against humanity after World War II, earning him the infamous nickname "Butcher of Tehran" among the Iranian people. He was one of the four officials on the Tehran "death commission" that oversaw a nationwide massacre of political prisoners in 1988. Ultimately, around 30,000 political prisoners were killed, over 90% of whom belonged to the main democratic opposition Mujahedin-e Khalq (MEK).

My own brother Mahmoud was serving a prison term in 1988 as a result of his taking part in rallies and distributing literature for the MEK. In 1988, my family was anticipating his release. But, instead, authorities summoned my other brother to Evin Prison in Tehran and informed him that Mahmoud had been executed. They did not even give us his body, and now more than 34 years later, we still have no definitive information about his final resting place.

Mahmoud Hassani's story is tragically typical of that which is still being told by tens of thousands of families who lost loved ones during the massacre and who have been crying out for accountability ever since.

Each of the plaintiffs in the court case we have filed against Raisi is a current supporter of the MEK, which has grown in strength and continues to challenge the regime as an existential threat.

During the recent uprisings, the regime's Parliamentary Speaker, Interior Minister, and a host of Friday Prayer Leaders made televised references to the MEK as the leading force for the protests and called for the suppression of its supporters. Chants of "Death to the Hypocrites [MEK]" are televised on a daily basis.

The regime is terrified of people power. Raisi's appointment last year was part of a broader strategy to save the regime by suppressing imminent protests by a restive population.

Since then, the regime has more than doubled its rate of executions compared to the previous year, while also initiating terrorist plots against the MEK's headquarters in Albania, as well as against high-profile Western supporters of the organization, such as former Secretary of State Mike Pompeo, as a lesson to hundreds of other international dignitaries.

These trends are indicative of Tehran's ongoing commitment to the strategies and concepts that underlay the 1988 massacre. And now Raisi and his regime are committing more murder against Iranian protesters.

Such crimes, coming more than three decades after the 1988 massacre, are vivid demonstrations of the Iranian regime's impunity.

Raisi's presidential appointment was described by Amnesty International at the time as a "grim reminder that impunity reigns supreme." The organization's secretary general said in no uncertain terms that instead of ascending to the regime's second-highest office, Raisi "should have been investigated for the crimes against humanity of murder, enforced disappearance, and torture."

But his ascendance to the presidency is no reason to give up on the prospect of such an investigation – not even a year after his inauguration.

If the international community wanted to end the era of Tehran's impunity, Raisi should have been barred from speaking at the U.N.

Still, the Iranian people have shown that they will not allow Raisi to escape justice. The regime's leaders must and will be put on trial for their heinous crimes. Our lawsuit is a step in that direction.

Ahmad Hassani is a mechanical engineer. He lives in Ottawa