US Attorney General Loretta Lynch (C) speaks during a press conference at the Department of Justice on March 24, 2016 in Washington, DC.  At left is FBI Director James Comey.
Lynch announced the unsealing of an indictment of seven Iranians on computer hacking charges.  / AFP / Mandel Ngan        (Photo credit should read MANDEL NGAN/AFP/Getty Images)
PHOTO: MANDEL NGAN/AFP/AFP/Getty Images
US Attorney General Loretta Lynch (C) speaks during a press conference at the Department of Justice on March 24, 2016 in Washington, DC. At left is FBI Director James Comey. Lynch announced the unsealing of an indictment of seven Iranians on computer hacking charges. / AFP / Mandel Ngan (Photo credit should read MANDEL NGAN/AFP/Getty Images)
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(CNN) —  

Former Attorney General Loretta Lynch on Sunday defended her handling of the Clinton email investigation, saying in a statement that she “never hesitated to make the hard decisions.”

The statement comes hours before ABC News airs a highly anticipated interview with former FBI Director James Comey to promote his forthcoming memoir, “A Higher Loyalty,” his first televised sit-down interview since he was fired by President Donald Trump last year.

Comey writes in the book that he found evidence which he felt could cast “serious doubt” on Lynch’s independence.

“Had it become public, the unverified material would undoubtedly have been used by political opponents to cast serious doubt on the attorney general’s independence in connection with the Clinton investigation,” Comey writes. He calls the material a “development still unknown to the American public to this day.”

Congressional investigators have raised questions about about any conversations Lynch had with Clinton staffer Amanda Renteria or former Democratic National Committee Chairwoman Rep. Debbie Wasserman Schultz about the email investigation.

In her statement Sunday, Lynch said: “At no time did I ever discuss any aspect of the investigation with anyone from the Clinton campaign or the DNC.”

In the book, Comey also says Lynch asked him to call the Clinton email probe “a matter” instead of an investigation, which to him seemed to align with the Clinton campaigns use of euphemisms to avoid using the word “investigation,” he wrote.

In her statement, Lynch defended her approach, saying that in her decades as a federal prosecutor, “I have never hesitated to make the hard decisions, guided by the Department of Justice’s core principles of integrity, independence and above all, always doing the right thing.

“The Justice Department’s handling of the Clinton email investigation under my leadership was no exception,” she said. “It was led by a team of non-partisan career prosecutors whose integrity cannot be overstated and whom I trusted to assess the facts and make a recommendation – one that I ultimately accepted because I thought the evidence and law warranted it.”

Lynch, an appointee of former President Barack Obama, told NBC News last week that Comey didn’t appear concerned by the decision to call Clinton investigation a “matter,” saying that meeting was “like any other we had where we talked about the issues. We had a full and open discussion about it,” and Comey never raised concerns.

After being fired by Trump last year, Comey testified before the Senate Intelligence Committee and discussed his interaction with Lynch.

Lynch told NBC her first response to the testimony was: “What is the issue here?”

“This was a very sensitive investigation, as everyone knew. And the issue when he and I sat down at that time, which I think was early in the fall of 2015, was whether or not we were ready as a department to confirm an investigation going on,” Lynch said. “We typically do not confirm or deny investigations into anything, with rare exceptions.”

CNN’s Clare Foran and Maegan Vazquez contributed to this report.