Two former Twitter employees have been charged with spying on user accounts on behalf of the Saudi Arabian government, according to The Washington Post.

One employee accessed more than 6,000 accounts

The Justice Department announced the charges today after one of the former employees was reportedly arrested. That suspect, Ahmad Abouammo, was charged with spying on three Twitter accounts for the government, according to the Post.

Another former employee was charged with accessing data on more than 6,000 Twitter accounts, including one tied to a confidant of murdered journalist and critic of the Saudi government, Jamal Khashoggi. A third man, who prosecutors said acted as an intermediary between the employees and the Saudi government, was also charged. Those two suspects are still at large.

According to the Post, prosecutors linked the three men to a charity operated by Crown Prince Mohammed bin Salman, who has been tied by US officials to Khashoggi’s killing and has worked to undermine dissidents in the country. Prosecutors reportedly found that the former employees had been seeking data on prominent critics of the government.

The charges outline a major breach of security for Silicon Valley. In a statement, a Twitter spokesperson said the company “limits access to sensitive account information to a limited group of trained and vetted employees.”

“We understand the incredible risks faced by many who use Twitter to share their perspectives with the world and to hold those in power accountable,” the spokesperson said. “We have tools in place to protect their privacy and their ability to do their vital work. We’re committed to protecting those who use our service to advocate for equality, individual freedoms, and human rights.”