An investigation in Louisiana revealed that bribes were being paid for favorable treatment in DWI cases. Three employees of the office have already plead guilty as the result of a federal investigation. A lawsuit has now been filed challenging the legitimacy of the plea. He claims a non-lawyer paid cash to the DA's office to secure plea deals for people, including one of the individuals in the current lawsuit.
I'll admit that I haven't seen the lawsuit, so I'm not sure what it's about. I also have no knowledge - or understanding of Louisiana - which is different from other States. However, I would question of wisdom of taking such action if the individuals are trying to invalidate their pleas.
In Texas you challenge a plea through a writ of habeas corpus. If you are successful your conviction is vacated and set aside, and you go back to the beginning. That means you go back to the place you were before you were convicted. You can go to trial, or work out deal, or convince the State to dismiss the case.There's no guarantee that you will come out better the second time. That's usually not a concern, because most successful claims involve some type of error that made the State's case stronger.
I'm not sure what the defendant's hope to obtain through their suit. Perhaps the prosecutorial misconduct is enough to result in a dismissal in Lousiana. If not, the defendant's may be worse off. You would hope that if you paid a bribe you got a better deal than if you hadn't paid a bribe - otherwise why do it. When you start over you don't have that advantage.
I'll be interested to see how this all turns out.