The murder of the Prophet's chief Jewish opponent, Ka‘b b. al-Ashraf, led to grave consequences for the tribe of Banū al-Naḍīr and for the Jews as a whole. The incident ushered in a series of hostile Muslim-Jewish encounters that reached its climax in the battle of Khaybar. Despite the constructive study undertaken by previous scholars, there still seem to be some contradictory elements and vague accounts that have been either utterly ignored or for which a satisfactory explanation is lacking. In the light of certain striking pieces of evidence, scattered in unlikely places in the sīra and tafsīr compendia, the present study sets out to examine critically the extent to which the accounts of Ka‘b's murder can be trusted. It will be argued that what we are faced with is seriously distorted material with logical absurdities and discrepancies that cannot easily be reconciled. Apart from the historical reconstruction, special attention will be devoted to a momentous historiographical point—that our reports have been doctored for political reasons. This helps us adopt a more realistic view of the individuals whose names occurred in the accounts of the event in question.