Hadith no. 2698 (below) is a repeat. Read it here.
Volume 4, Book 52, Number 301 :
Narrated by Anas (radiallaahu `anhu)
The Prophet (sallallaahu `alayhi wasallam) performed ‘Umra, setting out from Al-Jarana where he distributed the war booty of Hunain.
Volume 4, Book 52, Number 302 :
Narrated by Nafi
Once a slave of Ibn ‘Umar (radiallaahu `anhu) fled and joined the Byzantine. Khalid bin Al-Walid (radiallaahu `anhu) got him back and returned him to ‘Abdullah (bin ‘Umar) (radiallaahu `anhu). Once a horse of Ibn ‘Umar (radiallaahu `anhu) also ran away and followed the Byzantines, and he (i.e. Khalid) got it back and returned it to ‘Abdullah (radiallaahu `anhu).
Volume 4, Book 52, Number 303 :
Narrated by Ibn Umar (radiallaahu `anhu)
That he was riding a horse on the day, the Muslims fought (against the Byzantines), and the commander of the Muslim army was Khalid bin Al-Walid (radiallaahu `anhu) who had been appointed by Abu Bakr (radiallaahu `anhu). The enemy took the horse away, and when the enemy was defeated, Khalid (radiallaahu `anhu) returned the horse to him.
If a Muslim’s property is captured by non-Muslims and is returned as war booty to the Muslims, does the original owner have more right on it or the fighters? Scholars have disputed in this matter, but it looks like Imam Bukhari takes evidence in these ahadith from the fact that Khalid bin Waleed (radiallaahu `anhu) returned Ibn `Umar’s (radiallaahu `anhu) slave and horse to him without any hesitation. All the major sahaabah were present at that time, including Abu Bakr (radiallaahu `anhu). It’s highly unlikely of them to not speak up against a wrongdoing when they see it.
P.S. isn’t it funny how the slave that fled and the horse that was captured both belonged to Ibn `Umar (radiallaahu `anhu). Coincidence?
Read more on the ruling on war booty.