Rielle Hunter walked into the building through a back entrance and holding a young child.

Edwards adamantly denied during his confessional interview with ABC News last summer that he had fathered a child with Hunter, and he welcomed a paternity test. His wife, Elizabeth, has said while promoting her book that she doesn't know if her husband is the father.

Former Edwards aide Andrew Young, who made a similar appearance while the grand jury was sitting last month, has claimed to be the child's father.

Edwards has admitted to an affair with Hunter that he says ended in 2006. That year, Edwards' political action committee paid Hunter's video production firm $100,000 for work. Then the committee paid another $14,086 on April 1, 2007.

Edwards, a North Carolina senator from 1998 until his vice presidential bid in 2004, acknowledged in May that federal investigators are looking into how he used campaign funds. Grand jury proceedings are secret, and the U.S. attorney's office in Raleigh has declined to confirm or deny an investigation.

Young hasn't spoken publicly since saying he was the father in 2007 and has repeatedly ignored reporter requests for interviews.