[Kay Soze]

Chang is in prison because he bought a US Senator ( Torcelli) but Torcelli having sold himself is innocent.

I don't understand this.

[tsomer]

"Chang is in prison because he bought a US Senator ( Torcelli) but Torcelli having sold himself is innocent."

You are absolutely right! If Toricelli is innocent, Chang cannot be guilty, and vice versa.