The family of Majd Kamalmaz, an American psychotherapist who was detained at a government checkpoint in Damascus, Syria, in 2017, have filed a civil lawsuit against the Syrian government, accusing it of abducting, torturing and killing him. 

The lawsuit, filed Monday in federal court in Washington, D.C., on behalf of Kamalmaz’s four children, his widow and sister, accuses Syrian officials of deliberately killing the humanitarian and attempting to cover up his death.

His daughter, Maryam, told Fox News Digital last month that U.S. officials had presented the Kamalmaz family with classified information in May, saying they believe he died in Syria’s notorious prison system.

The lawsuit, filed under the Foreign Sovereign Immunities Act’s «state sponsor of terrorism» exception, seeks compensatory damages for wrongful death, assault and battery, intentional infliction of emotional distress and false imprisonment.

The plaintiffs also seek punitive damages, bringing the total claim to at least $70 million.

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«Today, on behalf of the Kamalmaz family, we have taken just the first step towards holding the Syrian regime accountable for its crimes against Majd Kamalmaz which culminated in his murder,» said Kirby Behre, lead counsel on behalf of the Kamalmaz family, according to a press release from the Syrian Emergency Task Force.

«The family filed this suit to bring international attention to Syria’s crimes against thousands of victims, and is counting on the U.S. government to initiate criminal charges against Syria.»

Majd Kamalmaz with his grandchildren. (Kamalmaz Family)

Kamalmaz was visiting an elderly family member at the time of his detainment and intended to establish a clinic in Syria to aid victims impacted by the civil war.

His daughter, Ula, told Fox News Digital earlier this year that the family was never given a reason for their father’s detainment because there was never a case or crime against him. 

She suggested her father could have been detained due to his American passport.

«He didn’t do anything,» she said. «He wasn’t very political, you know, the only thing he was doing was just … he was a psychotherapist working with refugees.» 

«They set up a temporary checkpoint, and it was set up to kidnap him. And they probably thought they could make money off of him. That’s how they do things in Syria. Now, unfortunately, they’ll detain the person, and they won’t let him loose until the family pays a really large amount to get him out,» Ula added. «So, it’s just very corrupt.»

Majd Kamalmaz was detained at a government checkpoint in Damascus, Syria, in 2017. (AP Photo)

The civil lawsuit alleges that Dr. Kamalmaz was unlawfully detained, falsely imprisoned and subjected to inhuman and unlawful treatment in notorious Syrian prisons, including the Mezzeh Military Airport, which is known for the «torture and murder of perceived enemies of the Syrian regime.»

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«Syrian officials and agents purposefully killed Mr. Kamalmaz. Acting in concert and with premeditation, these officials and agents deliberately killed Mr. Kamalmaz and attempted to cover up his death,» the lawsuit read in part. 

«The Syrian regime’s killing of Mr. Kamalmaz was designed to intimidate and terrorize the civilian population of Syria, the victims’ loved ones, and the international community.»

FILE PHOTO: A man walks past a banner depicting Syrian president Bashar al-Assad in Douma, outside Damascus, Syria, September 17, 2018.  (REUTERS/Marko Djurica/File Photo)

The U.S. government has a fund set up for victims of state-sponsored terrorism that could provide compensation for the Kamalmaz family should the court rule in their favor and award them damages. 

The United States Victims of State Sponsored Terrorism Fund can pay out claims, with a cap of $20 million per person, or $20 million to $35 million per family. Depending on the amount of money in the fund, the family could get a certain percentage of whatever award is given over several years.

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«I know that if my father was with me right now, he would not rest until all men, women and children are released from the Assad regime’s concentration camps,» said Maryam. «In his honor, we plan to hold the regime fully accountable for its crimes against Americans and Syrians alike, and we call on the U.S. Senate to urgently pass the Assad Anti-Normalization Act for the sake of Americans still held by this criminal regime.»