A joint report released Thursday by the Department of Homeland Security and FBI has shed light on how federal investigators concluded that Russia was behind the hacking of Democratic political institutions in the presidential election.

Without mentioning either by name, the 13-page document illustrates how Russian civilian and military actors compromised the Democratic National Committee’s internal communications network and hacked thousands of emails sent and received by Hillary Clinton’s campaign chairman, John Podesta, as well as other “U.S. government, political and private sector entities.”