He killed off the Communists in the party and also those who wanted to usurp the Wehrmacht. It was the smart move, because it allowed Hitler to gain the support of two of the most important groups he needed to win: The Industrialists, who were leery of Rohm’s stated goals of seizing the means of production, and The Wehrmacht, who were worried they would be replaced by the SA.
The Strasser brothers were leaders of the socialist wing of the party. Gregor was dealt with in the 'Night of the Long Knives" but Otto got away.
Al Stewart - The Last Day of June 1934 - YouTube
https://www.youtube.com/watch?v=1ip5ato4HSY
Lyrics
The morning is humming, it’s a quarter past nine
I should be working down in the vines
But I’m lying here with a good friend of mine
Watching the sun in her hair
I pick the grapes from the hills to the sea
The fields of France are a home to me
Ah, but today lying here is a good place to be
I can’t go anywhere
But as we slip in and out of embrace
Like some old and familiar place
Reflecting all of my dreams in her face like before
On the last day of June 1934
Just out of Cambridge in a narrow country lane
A bottle-green Bentley in the driving rain
Slips and skids round a corner, then pulls straight again
Heads up the drive to the door
The lights of the party shine over the fields
Where lovers and dancers watch Catherine wheels
And argue realities digging their heels
In a world that’s finished with war
And a lost wind of summer blows into the streets
Past the tramps in the alleyways, the rich in silk sheets
And Europe lies sleeping,
You feel her heartbeats through the floor
On the last day of June nineteenth
On the night that Ernst Roehm died voices rang out
In the rolling Bavarian hills
And swept through the cities and danced in the gutters
Grown strong like the joining of wills
Oh echoed away like a roar in the distance
In moonlight carved out of steel
Singing “All the lonely, so long and so long
You don’t know how I long, how I long
You can’t hold me, I’m strong now I’m strong
Stronger than your law”
I sit here now by the banks of the Rhine
Dipping my feet in the cold stream of time
And I know I’m a dreamer, I know I’m out of line
With the people I see everywhere
The couples pass by me, they’re looking so good
Their arms round each other, they head for the woods
They don’t care who Ernst Roehm was, no reason they should
Just a shadow that hangs in the air
But I thought I saw him cross over the hill
With a whole ghostly army of men at his heel
And struck in the moment it seemed to be real like before
On the last day of June nineteen thirty four