He’s been pretty open about what he was doing. Here’s a lawyer going over the publicly available evidence back when Tate was first arrested. Presumably the cops found more evidence in the 5 months since then and will show it in court.

https://youtu.be/Gs5b04hnfMQ

Tl;dw Tate publicly admitted to sex trafficking, kidnapping (through fraud), defrauding his girls, and tax evasion.

Evidence? You mean the evidence he himself broadcasted around the world?