DETROIT -- The Detroit Free Press reported Sunday morning some Detroit city officials are at the center of an ongoing federal corruption investigation, and at least one member is admitting to meeting with the FBI.

The federal investigation relates to the city's sludge recycling contract with Houston-based Synagro Technologies Inc. that City Council approved in November by a 5-4 vote despite protests from residents.

Council President Ken Cockrel Jr. said Monday that he met for about 90 minutes last Wednesday with the FBI.

Cockrel said he has not been involved in any wrongdoing and is not the target of any investigation.

"I do take public service and the concept of the public trust very seriously and I expect the same from my staff," said Cockrel.

The Free Press said FBI agents have obtained hidden camera footage of City Council President Ken Cockrel Jr.'s Chief of Staff, John Clark, accepting money.

Cockrel told Local 4 Clark resigned Wednesday, but he could not comment on the circumstances surrounding his resignation.

Jim Schaefer, one of the Free Press reporters who broke the story, told Local 4, "What we're being told is that the FBI is looking into the approval of this contract, what went into the approval of this contract, so I assume this means they're going to look at the members who voted in favor for it, to see what were the motivations for voting that way."

The Free Press said five council members voted in favor of the contract. They were Monica Conyers, Sheila Cockrel, Martha Reeves, Barbara-Rose Collins and Alberta Tinsley-Talabi.

Ken Cockrel Jr., Kwame Kenyatta, Brenda Jones and Joann Watson voted against the contract.