Is it permissible to establish a tribal fund to which individuals contribute for the purpose of paying blood money on behalf of a killer from the tribe, and is it permissible to take a portion of the blood money to place it in this fund, and is Zakat obligatory on the assets of this fund?

The general rule is that the blood money (diyya) for accidental killing (khata') and semi-intentional killing (shibh al-amd) is borne by the aqila (male relatives on the father's side). As for the blood money for intentional killing (amd), it is incumbent upon the killer himself and is not borne by the aqila, by the consensus of scholars.

If the tribe volunteers to assist the intentional killer with the blood money that became incumbent upon him, there is no harm in that. Rather, it is a form of consolation and kindness for which the doer is rewarded, provided that it does not become binding on the tribe, thereby encouraging intentional killing.

There is no objection to establishing a fund for such assistance, but it is not permissible to take any amount from the blood money from the victims by force, because the wealth of a Muslim is not lawful except with his willing consent.