For reference: Trotsky, Diary in Exile, p. 80-81:
"The White press at one time hotly debated the question of who it was that ordered the execution of the Tsar's family. The liberals, it seemed, inclined to the opinion that the Ural Regional Committee, being cut off from Moscow, had acted independently. That is not correct. The resolution was adopted in Moscow. The affair took place during a very critical period of the Civil War, when I was spending almost all my time at the Front, and my recollections about the case of the Tsar's family are rather fragmentary... My next visit to Moscow took place after the fall of Ekaterinburg. Talking to Sverdlov, I asked in passing, "Oh yes, and where is the Tsar?" "It's all over," he answered, "he has been shot." "And where is the family?" "And the family along with them." "All of them?" I asked, apparently with a touch of surprise. "All of them," replied Sverdlov, "what about it?" He was waiting to see my reaction. I made no reply. "And who made the decision?" I asked. "We decided it here. Ilyich [Lenin] believed that we shouldn't leave the Whites a live banner to rally round, especially under the present difficult circumstances." I did not ask any further questions, and considered the matter closed."
1920 Yurovsky note: "On July 16, a cable in previously agreed-upon language arrived from Perm, containing the order to execute the Romanovs."
King and Wilson analysis of both of above is in FOTR pp. 292-295. I have my own thoughts, naturally, and would be happy to provide them... But for now, back to my self-imposed exile! (Siberia is lovely in the summertime...)