It was narrated from Abu Umamah bin Sahl bin Hunaif that a man shot an arrow at another man and killed him, and he had no heir except a maternal uncle. Abu 'Ubaidah bin al-Jarrah wrote to ‘Umar concerning that and he wrote back saying that the Prophet ﷺ said:
`Allah and His Messenger are the guardians of the one who has no guardian, and the maternal uncle is the heir of the one who has no heir.”