Abu Qatadah (may Allah be pleased with him) reports that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever kills a disbeliever and has a witness to it, then the belongings of the slain will belong to him." Imam Tirmidhi says:
There is an incident mentioned in the hadith 1؎.

`Through this chain as well, a similar hadith is narrated from Abu Qatadah (may Allah be pleased with him).
1- This hadith is Hasan Sahih.
2- In this chapter, hadiths have also been narrated from Awf bin Malik, Khalid bin Walid, Anas, and Samurah bin Jundub (may Allah be pleased with them).
3- Some of the people of knowledge among the Companions and others have acted upon this, and this is also the saying of Awza'i, Shafi'i, and Ahmad.
4- And some of the people of knowledge say that the Imam has the authority to take out a fifth from the belongings of the slain. Sufyan al-Thawri says: «نفل» The correct view is that the Imam should announce that whoever seizes the belongings of the disbelievers, it will be his, and whoever kills a disbeliever, the belongings of the slain will be his, and this is permissible; there is no fifth (khums) obligatory in it. Ishaq bin Rahwayh says that the wealth of the slain belongs to the killer, except when the belongings are many and the Imam wishes to take out a fifth from it, as Umar bin Khattab did.