For more details check "The Execution of the Bāb in Early Bābī and Qājār Sources" A Short Comparative Source-Critical Analysis of the two early accounts of Nāṣikh al-tawārīkh and Nuqṭat’ul-kāf by Wahid Azal
The Baha'i narrative of the execution of the Bab is absent from the earliest historical sources.
For more details check "The Execution of the Bāb in Early Bābī and Qājār Sources" A Short Comparative Source-Critical Analysis of the two early accounts of Nāṣikh al-tawārīkh and Nuqṭat’ul-kāf by Wahid Azal