Despite the objection of an Ansarite, who had been among the captors and argued that the captives' inviolability should be respected due to their declaration of faith, Khalid had them all executed.
[4] Another reason for Malik's execution, according to historians, includes committing apostasy by refusing to acknowledge Muhammad as a prophet during his encounter with Khalid.
However, after they were defeated by rival clans from the Tamim, Malik abandoned her cause and retreated to his camp at al-Butah, where he and his small party were encountered by the Muslims.
[6][7] Additionally, other historical narrations suggest that Mutammim ibn Nuwayrah later affirmed Malik’s apostasy when Umar asked him to recite poetry about his brother.
[8] According to another report, Khalid's actions were deemed an error; however, when Umar called for his removal, Abu Bakr refused,[3] stating, "I will not sheathe a sword which God (Allah) has drawn for His service.