If corruptors returned all the looted money, it doesn't mean their records are clean, no crime was made by them. That's their responsibility to return all the looted money to the country, but the unlawful acts they have done are crimes, and crimes are not acceptable. Leave them or not will only be considered when they;
1- returned all looted money with extra 50% of the actual amount of looted money,
2- publicly accept their crimes,
3- publicly ask forgiveness from the nation and the state (nation or justice department will decide, I think nation is a better option)
4- make a promise that they will not do bad things again (also, agree on some conditions which will take place against them if they do bad things again)
After that "nation or Justice department will decide" (through a referendum or whatever fair method is) that they should be forgiven or not.