After the failure of the 1921 Syrian revolt that he led , al-Qassam escaped to Haifa . According to Shai Lachman , between 1921 and 1935 al-Qassam often cooperated with Mufti of Jerusalem Mohammad Amin al-Husayni . They were on good terms , and al-Qassam 's various official appointments required the mufti 's prior consent . He suggests their cooperation increased after the 1929 riots , in which one source claims al-Qassam 's men were active . The two fell out in the mid-thirties , perhaps due to al-Qassam 's independent line of activism . When the Mufti rejected his plans to divert funding marked for mosque repairs for the purchase of weaponry , Qassam found support in the Arab Nationalist Istiqlal Party . Qassam continued his attempts to forge an alliance with the Mufti in order to attack the British . He was not successful for the Mufti , who headed the Supreme Muslim Council , was still committed to a diplomatic approach at the time . Qassam went ahead with his plans to attack the British on his own
1929 riots
1929 Palestine riots
Black Hand (Mandatory Palestine)