Victor Mercado pleaded guilty to a single conspiracy charge in 2012 while on trial with Kilpatrick and others.
The FBI is investigating rumors that someone tried to bribe Detroit City Council members in an effort to influence the outcome of the race for council president.
They lined their own pockets while endangering Detroiters.
Taxpayers paid slightly more than $1 million for the legal defense of former Detroit Mayor Kwame Kilpatrick and his father.
The money would go to the Detroit water department.
Federal prosecutors want former Detroit Mayor Kwame Kilpatrick to pay about $4.5 million for widespread corruption under his watch.
The 72-year-old returns to court on Thursday, a week after Kwame Kilpatrick was sentenced to 28 years in prison.
Before he was sentenced, he read passages from the Bible but failed to apologize for his crimes.
Kwame Kilpatrick returns to court to face what is likely to be one of the longer sentences in recent cases of public corruption.
The U.S. Attorney in Detroit wants ex-Mayor Kwame Kilpatrick and his friend Bobby Ferguson to pay $9.6 million in restitution.