Musannaf Ibn Abi Shayba 18:1149

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Abdullah bin Habib bin Abi Thabit narrated to us, from ‘Amir, from Masruq, that six youths went to swim, and one of them drowned. Three [of them] testified against two that they had drowned him, and two [of them] testified against three that they had drowned him. So he (the judge) decreed upon the three [to pay] two-fifths of the blood money, and upon the two [to pay] three-fifths of the blood money.