Historian Martin Windrow wrote that in summer of 1944 Dirlewanger led his "butchers, rapists and looters into action against the Warsaw Uprising, and quickly committed ... unspeakable crimes."[21] In Warsaw, Dirlewanger participated in the Wola massacre, together with police units rounding up and shooting some 40,000 civilians, most of them in just two days.[2] In the same Wola district, Dirlewanger burned three hospitals with patients inside, while the nurses were "whipped, gang-raped and finally hanged naked, together with the doctors" to the accompaniment of the popular song "In München steht ein Hofbräuhaus".[1] Later, "they drank, raped and murdered their way through the Old Town, slaughtering civilians and fighters alike without distinction of age or sex."[3] In the Old Town – where about 30,000 civilians were killed – several thousand wounded in field hospitals overrun by the Germans were shot and set on fire with flamethrowers.[1] SS-Obergruppenführer Erich von dem Bach-Zelewski, overall commander of the forces pacifying Warsaw – and Dirlewanger's former superior officer in Belarus – described Dirlewanger as having "a typical mercenary nature".[22] After the war, Heinz Guderian claimed that as the chief-of-staff of the Army High Command, he advised Hitler to have Dirlewanger's unit withdrawn from the city, and that even Himmler's liaison officer Fegelein agreed by saying: "It's true, my Führer.