Why does Hizbullah want to veto the Harriri asination inquiry?

Hizbulla is so attached to Syria and Iran As we know that Hasan Nasrallah is use to be student in the Iran school and he loves Iran very much and so is Syria but why is going to use the veto .i think that he asks him self what is the aim of all this investigation the man is killed and there is a lot of ination happened before and after him the why this one specially everybody wanna know how and why he is been killed he thinks that America and the euro union is behind the inquiry to get Syria in the problem and force her to obey the role of the states in the middle east and Hizbulla doesn’t want that to happened so that’s why i think .....