Muwatta Malik #1547
Judgements
Malik related to me that he heard Ibn Shihab say, "The stray
camels in the time of Umar ibn al-Khattab were numerous and left
alone. No one touched them until the time of Uthman ibn Affan. He
ordered that they be publicised and then sold, and if the owner came
afterwards, he was given their price."
About Muwatta Malik
This hadith is #1547 from Muwatta Malik, in the Book of Judgements. Muwatta Malik contains 1,985 hadiths across 61 books.