There was a thread about this on FR recently, and an Italian Communist filmmaker depicted these events in The Damned. I thought it was just typical Communist defamation at the time. How wrong I was! (Yes, I admit it -- I was wrong, and a Commie Pinko was right!!!)
Hitler eliminated the Brown Shirts because he needed to get control of the Army and the cooperation of the industrialists, and the flaming homosexuals at the top of the SA (the top echelons were exclusively homosexual and bisexual) posed an embarrassment to the Nazi Party, particularly inasmuch as the leadership of the SA demanded control over the Army, which the Army brass just were not going to have. So Hitler eliminated the SA in the "Night of the Long Knives" (also depicted in The Damned); the liquidations were carried out by the SS, who hitherto had been a relatively small bodyguard. Of course the SS went on to become the army-sized Waffen SS, the SS-Ahnenerben, the death-camp corps, the international freiwilliger-SS corps (the Wallonien, Nordland, Charlemagne, and other divisions of the Waffen-SS), and all the rest of the multifarious, hydra-headed organization whose rollup and accounting for we still haven't fully completed, as we keep tripping over former freiwilliger SS death-camp guards in America.