General Colin Powell speaks at the TIME Summit On Higher Education at the Time Warner Center in New York City on Sept. 20, 2013. Getty Images

Hillary Clinton may have been encouraged to use her controversial private email server by a former secretary of state: Colin Powell. The New York Times reported exclusively Thursday night that Clinton, while being interviewed by the FBI about the information she sent and received on the personal account in office, told authorities Powell once "advised her" to keep a separate inbox.

The Times uncovered proof of the story in documents the FBI gave Congress earlier this week, but the concept wasn't new. In a book coming out next month, veteran journalist Joe Conason asserts that Powell recommended Clinton make use of a private email account while at a dinner party.

"Saying that his use of personal email had been transformative for the department, [he] thus confirmed a decision she had made months earlier — to keep her personal account and use it for most messages," Conason writes, according to the New York Times.

The duo also emailed about the personal email situation in 2009 — something Powell's office confirmed in a statement to Reuters.

"He did write former Secretary Clinton an email memo describing his use of his personal AOL email account for unclassified messages and how it vastly improved communications within the State Department," the statement read. "At the time there was no equivalent system within the department."

Hillary Clinton's Email Controversy | Graphiq

Powell, the United States secretary of state from 2001 to 2005, has admitted to using a private email on the job, but media outlets have pointed out several differences between his situation and Clinton's. The Washington Post noted that because Powell served during the infancy of email, the department didn't have such strict rules on what was allowed and what wasn't. CNN mentioned Powell, unlike Clinton, kept his emails on government servers.

Clinton has previously said she set up the private server out of convenience. "I thought it would be easier to carry just one device for my work and for my personal emails instead of two," she told reporters last year.

The FBI ultimately decided not to indict Clinton, now the Democratic nominee for president, for the scandal. Of the 30,000 emails Clinton handed over to the State Department, 110 were classified. Director James Comey said in July that although she'd been "extremely careless," he couldn't "find a case that would support bringing criminal charges on these facts."

Since then, Clinton's rival, Donald Trump, has ramped up his criticism of the former First Lady, honing in on the personal messages she deleted before turning over her cache for investigation.

"I think her email scandal is one of the worst things I've ever seen. She deleted 33,000 emails which is a crime, what she did is a crime, and to think that you have subpoenas and you're deleting emails, it's unthinkable," Trump told Fox News this week, according to Politico. "And I think probably her single greatest achievement in her life will be getting out of that mess because — and I don't think she's really out of it."