A UN-backed investigator's mobile phone was hacked during his investigation into possible war crimes in Yemen, forensic analysis of the device has revealed.

Kamel Jendoubi, a Tunisian who served as the Chairman of the now defunct Group of Eminent Experts in Yemen (GEE), a panel mandated by the UN to investigate possible war crimes, was targeted by "Israel's" NSO Group, as revealed after experts at Amnesty International and the University of Toronto's Citizen Lab analyzed his phone.

The targeting seems to have taken place weeks before Jendoubi's panel released a report that concluded that the Saudi-led coalition in Yemen had committed “serious violations of international humanitarian law” that could lead to “criminal responsibility for war crimes."

The expert's number was on the leaked database of the Pegasus Project, which was an investigation into NSO by media outlets, which was coordinated by French non-profit group Forbidden Stories.

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Saudi Arabia's shuts down the investigation

According to The Guardian, the data seems to show that Jendoubi was being monitored by Saudi Arabia, a longtime former client of NSO, who claimed to have dropped it earlier this year following reports of it abusing the spyware.

An NSO spokesperson told The Guardian, “Based on the details you have provided us we can confirm that Kamel Jendoubi was not targeted by any of our current customers."

The UN mandate to investigate the possible war crimes came to an sudden stop in October, after the members of the Human Rights Council voted to end the investigation. The Guardian had reported earlier that Saudi Arabia used “incentives and threats” to shut down the UN investigation.

What is Pegasus?

According to an investigation led by The Washington Post and 16 media partners that were published on July 18, Pegasus is military-grade spyware leased by NSO to governments who used it in attempted and successful hacks of 37 smartphones belonging to journalists, human rights activists, and business executives.

Smartphones infected with Israeli spyware would become pocket-spying devices, allowing the user to read the target's messages, look through their photos, track their location, and even turn on their camera without their knowledge.

The investigation discovered that 37 targeted smartphones were found on a list of more than 50,000 numbers concentrated in countries known to engage in citizen surveillance and also known to have been clients of NSO Group.

The numbers on the list are unattributed, but via research and interviews on four continents, reporters were able to identify more than 1,000 people from more than 50 countries. Several members of the Gulf royal families, at least 65 corporate leaders, 85 human rights activists, 189 journalists, and over 600 politicians and government officials, including cabinet ministers, ambassadors, and military officers, have all been targeted.