Threat of the SA - around 3 million members in Jan 1934 and Rohm wanted a second revolution - wanted SA to replace the existing army. Activities of the SA were difficult to control.
Goring, Himmler, and Heydrich - drew up the 'Reich list of Unwanted Persons'.
On 30th June 1934 Hitler arranged for the SS to kill many of his enemies. Eliminated leadership of the SA and many other political opponents of the Nazis.