Wikipedia
Haruriyyah
The Harūrī were an early Muslim sect from the period of the Four Rightly-Guided Caliphs (632-661 CE), named for their first leader, Habīb ibn-Yazīd al-Harūrī. The Harūrī were one branch of the Khārijī "Rejectors" movement, so called because they rejected ‘Alī's right to the Caliphate. While originally members of the "Party of ‘Alī", they turned against him when he agreed to arbitration regarding the issue of leadership and a Harūrī, Ibn Muljam assassinated ‘Alī while he was praying on 21 Ramaḍān in 661 CE.