Ahram Online has a lengthy excerpt from the memoir of the last surviving Free Officer, Khaled Mohieddin. (Though the caption on their photo of the Free Officers actually identifies his recently deceased cousin, Zakaria Mohieddin.) On his and Nasser's secret dealing with the Muslim Brotherhood:
I continued to read the books brought to me by Usman Fawzi and I constantly demanded that there be a clear programme for the Brotherhood, defining its national objectives and its position and demands of the various social categories. In my arguments, I began to lean to the left and I became the odd man out in a group supposedly affiliated to the Muslim Brotherhood.
In a final effort, Hasan El-Banna sought to link us with the Brotherhood via a strong bond. He decided that Nasser and I should join the Brotherhood's Secret Division. Perhaps it was because we were the most active and effective in our group and, consequently, winning us over completely would mean ultimately winning over the whole group.
Or perhaps it was because we talked much about the nation and nationalism and therefore he believed that by having us join the Secret Division, which was concerned with weaponry and armed action, he would be satisfying our patriotic enthusiasm and ensuring closer ties with the Brotherhood.
Anyway, we were contacted by Salah Khalifa, who took the two of us to a house in Darb Al-Ahmar toward Sayyida Zaynab. There we met Abd El-Rahman El-Sanadi, head of the Brotherhood's Secret Division at the time.
We were taken into a totally darkened room where we heard a voice (I think it was that of Saleh Ashmawi) and, placing our hands on the Quran and a gun and repeating after the voice, we took an oath of obedience and total allegiance, for better or worse, to the Grandmaster, swearing by the Book of God and the Sunna (traditions) of the Prophet. Although these rites were meant to stir the emotions, they had very little impact on Nasser and myself.
In any case, we began to work in the Secret Division and we were taken for training at a place near Helwan. Since we were officers, it was only natural that we were more knowledgeable about weapons than our training instructors. Nasser was not too happy with the situation and we felt alienated from the Brotherhood.Also, Al-Ahram's front page the next day; "The Army Carries Out a Peaceful Military Movement":