experience, Himmler decided that alternative methods of killing should be found. On Himmler's orders, by the spring of 1942, the camp at Auschwitz had been greatly expanded, including by the addition of gas chambers, where victims were killed using the poison gas Zyklon B. After the assassination of Reinhard Heydrich in June 1942, Wolff developed a strong rivalry with other SS leaders, particularly with Heydrich's successor at the Reich Security Main Office (Reichssicherheitshauptamt or RSHA), Ernst Kaltenbrunner, and with Walter Schellenberg of the foreign intelligence service in the RSHA. His position was weakened by his frequent absences from Berlin, in part due to his suffering from pyelitis and renal calculus (kidney stones), which required surgery. Wolff fell out of favour with Himmler and was dismissed as his chief of staff. In April 1943, he was relieved of his duties as liaison officer to Hitler. Himmler announced he would temporarily take over Wolff's duties. A new replacement as liaison officer to Hitler's HQ did not occur until the appointment of Hermann Fegelein, who assumed the duty in January 1944. Wolff had particularly angered Himmler by his divorce and remarriage in March 1943. Himmler, who believed the family to be the nucleus of the SS, had denied Wolff permission to divorce, but Wolff had turned directly to Hitler. Himmler still appears to have considered Wolff a loyal member of the SS, for in September 1943 Wolff was transferred to Italy as Supreme SS and Police Leader. In that position, Wolff shared responsibility for standard police-functions such as security, maintenance of prisons, supervision of concentration camps, and forced-labor camps - as well as the deportation of forced laborers with Wilhelm Harster, who was the Commander in Chief of the Security Police. When Wolff became Plenipotentiary General of the German Wehrmacht in July 1944, he also became responsible for anti-partisan warfare in occupied Italy. By now Wolff commanded the police and the entire rear army in Italy. So far Wolff's involvement in war crimes in Italy remains largely unclear, partially because source material on the degree to which SS units participated in Nazi security warfare is lacking. Although it seems as if US investigators were in possession of incriminating material in 1945 that indicated Wolff's approval of the executions that became known as the Ardeatine massacre, this evidence was deemed not sufficient for criminal charges. On 9 December 1944, Wolff was awarded the German