The U.S. Department of Justice has charged two former Twitter employees with spying for Saudi Arabia for allegedly gathering data on thousands of Twitter accounts on behalf of the kingdom starting in 2015. One of the former employees, Ahmad Abouammo, was arrested Tuesday. He’s a U.S. citizen who worked as media partnerships manager at Twitter, and the DOJ alleges he spied on three accounts, including a friend of the slain journalist Jamal Khashoggi who likewise spoke as one of the country’s most prominent critics. The second Twitter employee, Ali Alzabarah, is a Saudi citizen accused of gathering information on more than 6,000 Twitter accounts on behalf of the kingdom. Another Saudi citizen, Ahmed Almutairi, is also charged with spying for working as a go-between for the kingdom and the employees. Almutairi did not work at Twitter. Twitter thanked the FBI and the DOJ in a statement, saying “We recognize the lengths bad actors will go to try and undermine our service.”