Black Organisation in relation to Police

[Black Organisation in relation to Police]

I just remembered that Scotch was a member in B.O who was also working for the Tokyo police.

I can't remember if the police have ever investigated (apart from Scotch) B.O.

And if yes, why did they stop?

[Kogoro and Eri]

Why did Kogoro shoot Eri when she was victim to a criminal?

I forgot why and another question is why don`t they live together anymore? 
 

-first post.

Thank You.