Israeli civil rights organization Shurat Hadin (Israel Law Center) says it will file a claim against Hamas political chief Khaled Mashaal in the International Criminal Court.

“The claim alleges that Khaled Mashaal implements the murderous policies of the Hamas terrorist organization and thus facilitated the murder of 38 Palestinian citizens suspected of anti-Hamas activities and ‘collaboration’ with Israel,” the organization said in a press release. “According to international law, murdering citizens without trial constitutes a war crime.”

Over the course of Operation Protective Edge, Hamas reportedly executed at least 50 people suspected of cooperating with Israel. In some cases, witnesses said that Hamas operatives seized suspects in the street and killed them on the spot. Hamas has said that others who were arrested would stand trial.

Following a string of killings, both Israeli and Palestinian Authority officials accused Hamas of cold-blooded executions reminiscent of those perpetrated by Islamic State jihadists in Syria and Iraq.

The head of Shurat Hadin, attorney Nitzana Darshan-Leitner, said that Mashaal, unlike other Hamas leaders, is subject to prosecution by the ICC because he is a citizen of Jordan, which is a member of the court. Mashaal resides in Doha, Qatar.

“The court is obligated to exercise its authority over every crime committed by a citizen of a member country, wherever the crime was committed,” she said. “Therefore it can immediately investigate and prosecute Mashaal with respect to the 38 executions.”

Shurat Hadin’s announcement comes as the Palestinian Authority mulls joining the court and filing charges against Israeli officials. International Criminal Court Chief Prosecutor Fatou Bensouda has said that Palestine is a state that can make claims in the court, but that the court has yet to act because the Palestinians have not signed the Rome statute, the treaty that established the court.

The Palestinians were reluctant to join the court because it would open them up to the threat of legal action by Israel and other parties.

“Recently, Hamas added its signature to the Palestinian Authority’s request to become a member of the International Criminal Court. With this process, Hamas, which is so interested in being a member of the court, can get a taste of the hand of the court without the necessity of being a member,” Shurat Hadin added.

Times of Israel staff contributed to this report.