In 1947 he was tried for war crimes under Ukaz 43 by the Military Collegium of the Supreme Court of the Soviet Union, sentenced to death on 16 January 1947 and executed in Lefortovo Prison the same day.

Immediately after the war he fought in the ranks of the Volunteer Corps (Freikorps) against Polish separatists in Silesia and participated in the Kapp Putsch.

After spending a year in Hungary[citation needed], Pannwitz went to Poland in 1926, where he lived and worked as an administrator of farms, at the last in charge of the estates of Princess Radziwill[which?]

In late November 1941, during the arrival of fresh troops of the 6th Panzer Division by train at Kotelnikovo, hidden Soviet artillery began shelling the railway station.

Realising the danger, he co-opted the maintenance crews as drivers and gunners, and with six battle-worthy panzers attacked the Soviet batteries from the rear.

During punitive operations in Serbia and Croatia, the Cossack regiments under Pannwitz's command committed a number of atrocities against the civilian population including several mass rapes and routine summary executions.

[6] At the award ceremony in Berlin, when Pannwitz received the "Oak Leaves" for his Knight's Cross on 15 January 1943, he told Hitler that the official Nazi policies which caused Slavs to be regarded as subhumans (Untermenschen) for strategic reasons were totally wrong.

Before the end of the war, he was elected Feldataman (German rendering of Supreme Ataman, the highest rank in the Cossack hierarchy and one that was traditionally reserved for the Tsar alone).

[12] By his own request von Pannwitz was discharged from the army on 10 February 1945 and entered the SS in the rank of SS-Gruppenführer and lieutenant-general of the Waffen-SS the following day.

[13] Pannwitz surrendered on 11 May 1945 to British forces (Eighth Army's V Corps) near Völkermarkt in Carinthia, Austria, and tried to ensure that his men would remain in the custody of the Western Allies.

But on 26 May he was deprived of his command and placed under arrest by the British Army while the forcible loading of the Cossacks into trucks began, and continued through the following days.

[1] Almost fifty years later, on 23 April 1996, during the Russian presidency of Boris Yeltsin, members of the Pannwitz family petitioned for a posthumous reversal of the 1946 conviction.

The Military High Prosecutor in Moscow subsequently determined that Pannwitz was eligible for rehabilitation as a victim of Stalin-era repression.