Berthold's apartment at Tristanstraße in Berlin, where his brother Claus also lived for some time, was a meeting place for the 20 July conspirators, including their cousin Peter Yorck von Wartenburg.
Berthold was tried in the Volksgerichtshof ("People's Court") by Roland Freisler on 10 August and was one of eight conspirators executed by strangulation, hanged in Plötzensee Prison, Berlin, later that day.