His amazing and under-reported war against all who opposed his leadership resulted in 3000 murders and over 18,000 Arabs fleeing Palestine out of fear.
One man emerged as a rival to the Mufti. Fakhri Bey Nashashibi wrote a letter to the British High Commissioner in 1938 detailing the corruption and crimes of the supposed leader of the Palestinian Arabs:
Keep in mind that then, as today, "moderate" is a relative term. It is clear that Fakhri Bey was against partition, he was against legally selling any land to Jews to the point of condoning murder, he supported terror against Jews. But he was against corruption and against the Mufti.
His fight to marginalize the Mufti intensified in 1939, with a detailed letter to Arab leaders with more accusations against the Mufti, where censorship did not allow his original letter to become known to the mainstream Arab communities. Particularly stinging was his accusations of how money meant for charities were being diverted to the Mufti terror campaign, and how "no school was opened, no hospital built, no mosque erected, anywhere in Palestine during the long years of Haj Amin's administration."
The end of the story is predictable. Fakhri Bey was murdered by a "Palestinian terrorist" in Baghdad in November, 1941.