(CNN) -- A "sizable" number of subpoenas have been issued in the investigation of former Sen. John Edwards, his attorney said.
Wade Smith, the attorney, said Wednesday he did not know who asked for the subpoenas or who was summoned. However, Smith said he maintained Edwards is innocent and said they welcome the government scrutiny.
A North Carolina federal grand jury has been investigating payments the former senator's campaign and supporters made to Rielle Hunter, his mistress who also worked as a videographer for his campaign.
As Edwards campaigned for the Democratic presidential nomination in 2008, allegations began to surface that he had an affair with Hunter as well as he was the father of Hunter's young child.
Edwards and his wife, Elizabeth, became legally separated after the scandal.