Since we're the ones who did most of the investigative work, there's not much left for you to do.
ご質問ありがとうございます。
「私たちが全て[調べた](https://eikaiwa.dmm.com/uknow/questions/7990/)から、あなたはできることないよ。」と言いたいなら、英語で「Since we're the ones who did most of the investigative work, there's not much left for you to do.」と言えます。
ご参考になれば幸いです。