Narrated Anas:
"Qais bin Sa'd used to be, to the Prophet (ﷺ), in the position of the head of police for a ruler." (One of the narrators) Al-Ansari said: "That is: Due to his affairs that he takes charge of." (IT)
English reference (IT): Vol. 1, Book 46, Hadith 3850 (IT)
Arabic reference (IT): Book 49, Hadith 4221 (IT)