It was first written off as a sex ring, but that didn't make any sense. Who is going to pay $2,000 to have sex with a 12 year-old black boy, when you have hundreds of 10 year-old white Ukrainian girls all over Tel Aviv. But someone is paying $3,000 a kid wholesale, and the reason is black market organs.
It's just economics in organ trading. You bring in a 12 year-old into Tel Aviv, and you don't just grab one $5,000 kidney, and then spend $200,000 raising the kid through college. That kid hits the operating table and he has kidneys, liver, cornea, heart, lung, marrow, etc., and everything is removed. That kid is murdered for his organs. It happens in Israel because of the security needed to cover the operation.
The kidnappers get $3,000 a kid, and all the organs can bring $150,000.