C. F. Keil and Franz Delitzsch on Numbers 31:11-12

Num 31:11-12

All this booty (shalal, booty in goods), and all the prey in man and beast (malkoach), was brought by the conquerors to Moses and Eleazar and the congregation, into the camp in the steppes of Moab. In Num 31:12, שׁבי applies to the women and children who were taken prisoners, מלקוח to the cattle taken as booty, and שׁלל to the rest of the prey.