Musannaf Ibn Abi Shayba 6:528

Muhammad ibn Abi ‘Adi narrated to us, from Ibn ‘Awn, who said: Muhammad [ibn Sirin] used to like to pray over the funeral, then pray the Afternoon (Asr) prayer. And he used to dislike praying over the funeral after the Afternoon prayer. He said: "Yes, if it is pure and white (i.e., the sun is still bright). But if it has approached the time of setting, then do not pray over it until the sun has set."