Washington ? Prosecutors have obtained emails between John Edwards and a former aide to use as evidence at trial that he knew about payments to his pregnant mistress even while he was publicly denying it, people familiar with the case told The Associated Press on Monday.

Dozens of emails were exchanged between Edwards and his former speechwriter Wendy Button as they worked on a never-released draft statement to acknowledge paternity of his out-of-wedlock child, according to people who have seen the messages and requested anonymity because they have not been made public yet.

The messages, draft statements and notes of their related phone conversations are key evidence prosecutors are using against Edwards, indicted on charges he failed to report nearly $1 million allegedly spent to keep his mistress out of the public eye as he pursued the White House. The former senator was still denying he was the baby’s father and publicly maintained he knew nothing about any money that may have been spent when the emails were sent in summer 2009.

Prosecutors must prove the 2004 vice presidential nominee had knowledge of the payments to convict him in the campaign finance case. Edwards proclaimed his innocence of any crime after being indicted Friday.

His attorneys declined to comment on the evidence revealed to the AP.

The six felony charges came after intense negotiations in which prosecutors first insisted Edwards plead to a felony, but they ultimately offered him the chance to plead guilty to misdemeanor charges and serve a jail sentence, according to people with knowledge of the talks who requested anonymity to discuss the private discussions. Edwards, a single father since his estranged wife’s death in December, was interested in reaching a deal but refused to accept anything that would take him away from his children, according to a person close to the talks. By definition, a misdemeanor could carry jail time of no more than one year.