Here are key figures in the FBI's corruption probe into City Hall that centers on the Synagro sludge contract:
James Rosendall Jr ., 44: Former vice president of Synagro Technologies. He pleaded guilty Monday to bribing city officials, who approved a sludge-hauling contract worth at least $47 million a year to Synagro. He is cooperating with authorities, wore a wire and videotaped giving money to city officials.
Rayford W. Jackson, 44: Rosendall's local partner in the Synagro deal. He's under investigation by the FBI in connection with Synagro.
Kwame Kilpatrick , 38: Former mayor, jailed in October for text-message scandal. Kilpatrick appears to be the "City Official A" listed in federal documents as having received campaign contributions and free flights from Rosendall.
Bernard Kilpatrick , 67: Father of former mayor, former top aide to deceased Wayne County Executive Ed McNamara. FBI agents are investigating payments to the consulting company, Maestro & Associates, that he ran while his son was mayor. He appears to be "Relative of City Official A" accused of receiving at least $25,000 from Rosendall for facilitating contracts.
Derrick A. Miller , 38: One-time top aide to Kwame Kilpatrick. Miller was chief administrative officer and chief information officer before leaving City Hall in November 2007 to form Citivest Capital Partners LLC. The FBI is investigating him in connection with a security contract and the failed Asian Village development.
Michael Tardif , 33: Democratic political consultant, paid by Kilpatrick from political funds, reportedly cooperating with the FBI investigation of City Hall corruption.
Monica Conyers , 44: City Council president. She cast the deciding vote on the Synagro contract, allowing it to pass. Federal officials have electronic surveillance information allegedly linking Conyers to payment or payments. Her aides also have been subpoenaed. Conyers denies wrongdoing.
Martha Reeves , 67: City Council member. She acknowledges the FBI tried to make contact with her, but hasn't said whether she was interviewed.
Sam Riddle , 62: A longtime political consultant and former aide to Conyers. He's said he believes the FBI tapped his phone.
John Clark , 37: Former chief of staff to then-Council President Kenneth Cockrel Jr., who is now mayor. Cockrel says FBI agents showed him tape of Clark accepting cash, presumably from Rosendall. Clark resigned and hasn't been charged.
Karl Kado , 67: A onetime contractor at Cobo Center. He faces charges of filing false federal tax returns and is accused of bribing Cobo officials. He's cooperating with federal agents.
Lou Pavledes , 54: Former director of Cobo Center. He pleaded guilty last year to violating currency reporting laws in connection with a series of cash deposits. He claims he received nearly $100,000 in bribes from Kado. Pavledes is cooperating with federal agents.
Glenn Blanton , 47: Former director of Cobo Center. He pleaded guilty to obstruction of justice in October; claims he accepted $15,000 in bribes from Kado.
Akunna Olumba, 32: A business associate and former girlfriend of Bernard Kilpatrick, she got a cut of a city recycling contract.