A federal grand jury has indicted former U.S. Senator and presidential candidate John Edwards on charges he violated campaign finance laws by using political donations to keep an extramarital affair secret.

The case includes six counts — one count of conspiracy, four counts of illegal campaign contributions and one count of false statements. It was filed on Friday in Edwards' home state of North Carolina.

Reports that Edwards' lawyer, Gregory Craig, would be in North Carolina Friday had fueled speculation that federal prosecutors were ready to indict Edwards or were negotiating a plea agreement with him in order to avoid a trial. Edwards resides in North Carolina and was elected to the U.S. Senate from there in 1998.

The case centers on money paid to Edwards' mistress, Rielle Hunter, with whom he fathered a child, and to a former aide, Andrew Young, who previously claimed paternity of the girl.

The money came from two wealthy supporters of Edwards' 2008 presidential campaign, and prosecutors say the funds should have been reported as campaign donations. His lawyers said he did not break the law. They said the money was a gift that was intended to keep the affair secret from his wife, Elizabeth.

Elizabeth Edwards died last year after a long battle with cancer.