JERUSALEM — A Canada-based Saudi activist filed suit this week against an Israeli cybersecurity firm, alleging that the Saudi government used the firm’s spyware to hack his cellphone and access sensitive conversations he conducted with slain Saudi journalist Jamal Khashoggi.

Attorneys for Omar Abdulaziz, 27, who is based in Montreal, lodged a civil case against the NSO Group in Tel Aviv on Sunday, legal papers show. The opposition activist has said he learned that his phone had been hacked in August, some two months after he clicked on an infected link.

The Citizen Lab, a University of Toronto project that investigates digital espionage aimed at civil society, concluded with “high confidence” that the Saudi government targeted his cellphone using Pegasus spyware created by NSO. 

Before being notified that his phone had been hacked, Abdulaziz was in regular contact with Khashoggi, with whom he had struck up a friendship. Khashoggi, a contributor to The Washington Post’s Global Opinions section and a critic of the kingdom, was killed in the Saudi Consulate in Istanbul on Oct. 2 by members of a 15-man team from Saudi Arabia. 

Saudi Arabia has dismissed two senior officials close to Crown Prince Mohammed bin Salman, the kingdom’s de facto ruler, in connection with the killing but denies that the crown prince knew of the operation. 

The legal filing argues that the Israeli software provided the Saudis with knowledge of conversations between Abdulaziz and Khashoggi about projects they were working on. The sophisticated software enables the operator to access all information stored on a target’s phone and to secretly film or record audio. 

Saudi Arabia's public prosecutor said Crown Prince Mohammed bin Salman had no knowledge of the operation. The CIA's latest findings contradict that assertion. (Joyce Lee, Jason Aldag, Monica Akhtar/The Washington Post)

“The details of this collaboration were known to the authorities in the Kingdom through the Pegasus system,” the court papers say. 

The filing says Abdulaziz will argue that use of Pegasus spyware to expose his communications with Khashoggi contributed to the decision to murder him.

In their exchanges, Abdulaziz has said, Khashoggi asked him to help design a website advocating human rights in the Middle East and assist with a logo for a foundation Khashoggi planned to set up called Democracy for Arab World Now.

Khashoggi also discussed sending Abdulaziz funding for a project the two called “the bees,” which involved buying foreign SIM cards for activists in Saudi Arabia who wanted to open Twitter accounts critical of the government and feared being traced on their Saudi SIM cards

Khashoggi was also directly critical of the crown prince in WhatsApp messages to Abdulaziz, according to images provided to The Post by Abdulaziz, describing him as a “pac-man” who devours his critics. 

In a statement to Israel’s Haaretz newspaper, the NSO group called the case “baseless” and said there is no evidence that its technology was used to hack Abdulaziz’s phone.  

“NSO is a technology company that is uninvolved with how our products are used once they are sold to our customers,” it said. “This is a lawsuit based on sensationalist journalism.”

The NSO spyware also has been used to target two Saudi activists in London and an Amnesty International researcher, according to the Citizen Lab.