The charges, unveiled Wednesday in San Francisco, came a day after the arrest of one of the former Twitter employees, Ahmad Abouammo, a U.S. citizen who is alleged to have spied on the accounts of three users — including one whose posts discussed the inner workings of the Saudi leadership — on behalf of the government in Riyadh.

Abouammo is also charged with falsifying an invoice to obstruct an FBI investigation.

The second former Twitter employee — Ali Alzabarah, a Saudi citizen — was accused of accessing the personal information of more than 6,000 Twitter accounts in 2015 on behalf of Saudi Arabia. One of those accounts belonged to a prominent dissident, Omar Abdulaziz, who later became close to Khashoggi, a Washington Post columnist who advocated for free expression in the Arab world.

Prosecutors said a third individual, Saudi citizen Ahmed Almutairi, acted as an intermediary between Saudi officials and the Twitter employees. He is also charged with spying. Alzabarah and Almutairi are believed to be in Saudi Arabia.