Updated at 2:08 p.m. on April 13

Former FBI Director James Comey has some choice words for former Attorney General Loretta Lynch in his new book, suggesting she was torn by his handling of the FBI's investigation into Hillary Clinton's unauthorized email server and hints that there may yet be more information, which has yet to be released, calling into question her partiality.

The excerpts leaked Thursday from his memoir, "A Higher Loyalty: Truth, Lies, and Leadership," are just the latest salvo in a back-and-forth between the two former federal law enforcement giants.

[Also read: James Comey didn't spill beans on Loretta Lynch bombshell because 'he was duped by a fake email': Longtime Clinton aide]

Comey writes Lynch possessed a "tortured half-out, half-in approach" to the emails inquiry. Comey describes how Lynch met with him privately just before the Nov. 8 election, and she embraced him and indicated that he had done the right thing, according to the Washington Post.

But at the end of the meeting, Comey says Lynch took a different tone. “She said, with just the slightest hint of a smile, ‘Try to look beat up.’ She had told somebody she was going to chew me out for what I had done," Comey says, adding, "What a world."

Comey also says he considered calling for a special prosecutor.

Comey, who was fired by President Trump last spring, stirred controversy for reopening the Clinton case in late October 2016 after the FBI found a new batch of emails. A couple days before the election, Comey revealed the case had been closed again and that the FBI maintained its prior position that no charges should be brought against Clinton. Despite this, Clinton herself has repeatedly heaped blame on Comey for contributing to her demise in the 2016 presidential election.

Lynch has seen her name and reputation dragged because of her controversial tarmac meeting with former President Bill Clinton in 2016 amid the presidential campaign. She denied that the Clinton email probe was broached, and it was soon afterwards that Comey announced for the first time that the emails case was being closed. He did condemn Clinton for her "extremely careless" behavior, however.

Last year, Comey told the Senate Intelligence Committee that Lynch requested he minimize Clinton’s email investigation, urging him to call it a "matter" instead of an "investigation," a request which he said bothered him and some have speculated was to avoid associating Clinton with a negative issue as she ran for president.

Pre-empting Comey's book release and accompanying media blitz, Lynch did an interview with "NBC Nightly News" anchor Lester Holt, which aired Monday, countering Comey's testimony.

"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, when we typically do not confirm or deny investigations into anything with rare exceptions," Lynch told Holt when asked about her pressing Comey on calling the emails investigation a "matter."

"It was a meeting like any other that we — that we had had where we talked about the issues. And we had a full and open discussion about it," Lynch said about her talk with Comey. "And concerns were not raised."

But Comey teases there may still yet be more to the story.

In his book, Comey says "unverified" information discovered by the U.S. government in 2016 from a classified source "would undoubtedly have been used by political opponents to cast serious doubt on the attorney general’s independence in connection with the Clinton investigation."

[Related: Kellyanne Conway: James Comey hyping his few meetings with Trump to sell books]

According to ABC News, he refers to this as a “development still unknown to the American public to this day," but his book does not go into further detail.

A longtime aide to Hillary Clinton claims to know what Comey is referencing.

"He omitted it bc it’s embarrassing & makes him look like a fool. He was duped by a fake email." tweeted Philippe Reines, who assisted Clinton in the State Department and her 2016 campaign.

Reines shared a Washington Post report, which is largely sourced with unnamed current on former officials, focusing on a "secret document" that was key in Comey's handling of the FBI's investigation into Clinton's unauthorized email server. The sources in the report describe the document as being from Russia, dubious in its reliability, quite possibly fake. The report cites a "supposed" email detailing how Lynch privately assured a senior Clinton campaign staffer named Amanda Renteria that the email probe would not dive too deep.

Comey's book is set to hit bookshelves on April 17.