When the distant brother started, he was 12 or 13. He was leaking intel before it from the looks of it.
He was suspected for murdering Shisui and they had sent the latter after him but Shisui betrayed them in the sense that he was never for the coup in the first place.
I don't believe he leaked any intel before Shisui's death, only after when he was Anbu captain. And if we were to use those novels as canon, they state this.
The suspicion (of him being a traitor) was too early, but it later proved to be true anyway. So, it really doesn't matter all that much in the end, I guess.