Friday marked Derrick Miller's fourth day to testify and the 52nd day of the corruption trial against Kilpatrick, his father Bernard and Bobby Ferguson, a longtime friend of the former mayor, The Detroit News reported.
The Kilpatricks and Ferguson are facing a number of charges, including alleged bid-rigging and kickbacks.
Kilpatrick lawyer James C. Thomas focused his questioning Friday on Miller's memory, as the witness previously said he couldn't remember details surrounding the alleged payoffs.
At one point, Thomas asked if Miller remembered being charged with racketeering conspiracy alongside Kilpatrick in December 2010.
"I don't remember all the charges," Miller said.
"You don't remember being charged with racketeering?" Thomas asked.
"Was that one of the charges?" Miller said.
Meanwhile, Kwame Kilpatrick showed up in court Friday wearing a Global Positioning System ankle bracelet, the Detroit Free Press reported.
Kilpatrick is confined to his mother's house while the Michigan Department of Corrections investigates whether he violated parole.