You mean, is there someone who can force him to drop everything else that he's working on and let all the other cases he's responsible for sit, while he works exclusively on yours?
No, there isn't.
This isn't Law and Order. The investigators are not working exclusively on one case. An investigation takes as long as it takes. It's not a question of "working faster"; it's a question of what kinds of evidence he has to work with. He may have to wait for other people to get back to him, or to have documents reviewed by outside sources. And those outside sources also have other cases to work on as well. What makes your case so special that it should get individual attention?
Two things I am tired of typing: 1.) A wrongful termination does not mean that you were fired for something you didn't do; it means that you were fired for a reason prohibited by law. 2.) The above answer, whatever it is, assumes that no legally binding contract or CBA expressly says otherwise. If it does, the terms of the contract apply.