DETROIT -- Several people, including a well-known Detroit businessman, Kevin Ransom, testified before a grand jury Tuesday as part of a federal investigation into the Synagro Technologies sludge contract.

Ransom is the owner of Sweet Georgia Brown, and close friend and business associate of Rayford Jackson, who is at the center of the FBI's probe.

Jackson was allegedly contracted by Texas-based Synagro to get Detroit politicians and Detroit City Council to accept a $47 million sludge contract.

While investigating the Synagro deal, the FBI wiretapped Jackson, Synagro Technologies executive James Rosendall and Bernard Kilpatrick, outgoing Detroit Mayor Kwame Kilpatrick's father, sources close to the investigation said.

WJBK-TV Anchor Fanchon Stinger, who was romantically linked to Jackson, no longer works for Fox 2 News while the company looks into Stinger's dealings with the contract between council and Synagro Technologies.

A Synagro spokeswoman says a consulting firm created by Stinger had done advertising work for the Houston-based waste hauler.

Detroit City Councilwoman Sheila Cockrel spent more than an hour testifying before a grand jury in the Synagro probe last week.

Sheila Cockrel emerged from the federal courthouse Wednesday afternoon and said the investigation is "wide-ranging."

She said she would not share details of her grand jury testimony with anyone. However, she did say she was not a target of the investigation.

Federal authorities are investigating possible payoffs to as many as four council members and other city officials in connection with the contract approved in 2007.

The deal awarded Synagro a contract to dispose of sludge produced by the city's waste and water treatment facilities.

Local 4 reported potential targets in the investigation include Mayor Kwame Kilpatrick, Bernard Kilpatrick and as many as four city council members who changed their vote last year from no to yes.

The investigation has been under way for three years.

Sources told Local 4 that several federal indictments are expected before the end of the year.