Newly declassified documents reveal diplomats at the U.S. Embassy in Jakarta, Indonesia, knew about—and supported—a mass extermination campaign by Indonesia’s government in the 1960s that killed hundreds of thousands of civilians—by some estimates, more than 1 million people. Beginning in 1965, Indonesian military and paramilitary forces slaughtered accused communists and dissidents after overthrowing the democratically elected government. That military was backed by the administration of President Lyndon Johnson and led by General Suharto, who would go on to rule Indonesia for decades. In memos made public on Tuesday, U.S. Embassy officials cheered reports describing the “slaughter” and “indiscriminate killings” of Indonesians. One memo from late 1965 read, “Generally victims are taken out of populous areas before being killed and bodies are buried rather than thrown in river.” Historians have already established that the U.S. provided the Indonesian Army with financial, military and intelligence support at the time of the mass killings.