Q. Some individuals and groups believe there is a Prophet after Muhammad, peace be upon him. Is this acceptable?

A. It is a tenet of Islam to believe that there is no Prophet with or after the Seal of Prophets -- Muhammad -- Peace be upon him. There is consensus among the scholars that to deny or question such a belief constitutes apostasy (kufr).

Sources: Ibn Hazm, Maratib al-Ijma` 173 Nawawi, Sharh Sahih Muslim 10:406.