On July 20, 1944, there was a failed assassination attempt on Adolf Hitler. As a result, 180 to 200 plotters were “shot or hanged, or viciously strangled with piano wire.” Through Dietrich Bonhoeffer was already in prison, he knew of the plot…

Bonhoeffer was among those who knew when this last assassination attempt was about to take place. He had great hopes for it, so hos quiet reaction to its failure was remarkable. He scarcely allowed for it to interrupt his ongoing theological work. He did know that from then on his life was in even greater danger than it had already been. 

(Ferdinand SchlingensiepenDietrich Bonhoeffer 1906-1945: Martyr, Thinker, Man of Resistance, 357).