I dont know.
THREE characters give me a creepy vibe like they are hiding something:
3. Agasa
2. Jodie (Remember the episode she first encounters the BO, she was very creepy in this episode)
1. Eri (I have reasons. Here is my short version of this theory: Eri is the BO Boss. She is very secretive and hides things. The reason Vermouth wont touch him, is that possibly, Vermouth, Eri and Yukiko could of been friends at one time. Due to this, she, nor Vermouth, will hurt Shinichi or Ran, and protect them. Next, we have other reasons. Eri seems to treat conan oddly and more like he is older then she sees him. Shes not stupid. Ran and Shinichi always use to be friends and Eri knowns him. She likely sees conan and notices he is a replica of Shinichi when he was 7. Later, she somehow likely finds out Conan is shinichi. Through Vermouth or some other means. She keeps this secret, but probably knows.)
Eri is the one i believe who is actually the real BO member. I have more reasons, but im very tired. I will add them later.