Jaroslaw Kaczynski, the leader of Poland's primary populist party and the country's former prime minister, appeared before a parliamentary commission on Friday to address accusations regarding the use of the Israeli spyware Pegasus during the party's leadership of Poland's previous government.

The Law and Justice (PiS) party, in power from 2015 to 2023, is under suspicion of having spied on opposition politicians and judges who were critical of its administration.

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Developed by the Israeli NSO Group, Pegasus, which can seize control of a smartphone's microphone and camera, hit global headlines when a leak in 2021 showed how governments used it to spy on critics, journalists, and NGOs.

In 2022, Kaczynski admitted that his government purchased the notorious spyware software but denied that it had been used against the opposition.

Ahead of Friday's inquiry, the head of the commission, Magdalena Sroka, said

The party leader was chosen to testify first because of his "responsibility for the actions of the Law and Justice Party, which was in power until 2023," the head of the commission said ahead of the Friday probe.

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Magdalena Sroka added that buying and operating Pegasus had "no basis" in law.

The parliamentary commission will review the purposes and legality of employing Pegasus, as well as attempt to determine the acquisition process of this and other similar systems by Poland.

Multiple sources within the new governing coalition led by Prime Minister Donald Tusk said that the undisclosed list of individuals to be interrogated could be "very long" and "shocking".

Citizen Lab, a Canada-based cybersecurity specialist group, reported that the Israeli spyware was utilized against multiple individuals in Poland.

Among the targets was Krzysztof Brejza, a current member of the European Parliament and former coordinator of the electoral campaign for the opposition party Civic Platform during the 2019 parliamentary elections.

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The new Polish parliament has initiated two additional inquiry committees regarding the actions of Kaczynski's previous government. One concerning the unsuccessful organization of presidential elections during the COVID-19 pandemic, and another regarding the widespread issuance of paid-for Polish visas by consulates in different countries.

NSO, which faces multiple lawsuits from Apple and others, has repeatedly insisted it sells its software only to government clients and only for peaceful purposes.

But the 2021 leak suggested there were around 50,000 potential victims of Pegasus around the world, many of whom were opposition figures, journalists, and activists.