Meanwhile, behind closed doors in Moscow, a bureaucratic battle had begun over the joint Report on the Causes of the Accident in Unit Four of the Chernobyl AES, the confidential version of events being prepared for the Politburo. In memos, meetings, and multiple interim documents, the barons of the Soviet nuclear industry—the scientists and the heads of the competing ministries that controlled it—competed to divert blame from themselves, ideally before the final report reached General Secretary Gorbachev.