The FBI's Clinton Foundation investigation was reportedly based on 'news stories and the book Clinton Cash'

The FBI launched its investigation into the Clinton Foundation based on news stories and information in the book "Clinton Cash," The New York Times reported on Tuesday, citing law enforcement officials.

The detail was included in a larger story about the FBI's decision to announce that it was looking into new documents related to the Hillary Clinton email investigation - which was closed in July - and how it broke with its policy over the summer to refrain from publicizing cases about either candidate so close to the election.

Those cases centered on Donald Trump's former campaign manager Paul Manafort's ties to Russian interests in Ukraine and the Clinton Foundation.

Both cases are still open, according to the Times. The probe into Manafort's foreign dealings are based largely on his work advising the former president of Ukraine and his pro-Russian political party, which earmarked $12.7 million in undisclosed cash payments for the former Trump campaign manager between 2007 and 2012.

The investigation into the Clinton Foundation, meanwhile, was reportedly inspired largely by the book "Clinton Cash," a book published in 2015 and written by a Clinton critic. The book claimed the Foundation traded favors and access for money while Clinton served in the State Department between 2009 and 2013.

The Clinton Foundation has accepted millions of dollars from foreign actors including Saudi Arabia, Qatar, and the United Arab Emirates. But the money was donated either before or after Clinton's tenure as Secretary of State, according to PolitiFact.

Peter Schweizer, the author of "Clinton Cash" and an editor at large at the alt-right media outlet Breitbart - whose on-leave executive chairman, Stephen Bannon, is now the CEO of the Trump campaign - told NBC in April that he didn't have direct evidence proving that Hillary Clinton traded favors for money while she was at the State Department.

Developments since last week have laid bare internal strife both within the FBI and between the FBI and the Justice Department in multiple inquiries involving Clinton.

Some agents were apparently frustrated with the FBI leadership's lack of interest in aggressively investigating the Clinton Foundation, as prosecutors within the public-integrity section of the Justice Department - who are not politically appointed - reportedly pressured the bureau to drop the investigation.

The prosecutors, and some within the agency, were worried that they would be perceived as trying to influence the outcome of the election if they pursued the Clinton Foundation investigation, both the Wall Street Journal and the New York Times have reported this week.

Adding to that perception over the weekend was the revelation that the FBI had not obtained a separate warrant to sift through the roughly 650,000 Clinton emails found on disgraced former congressman Anthony Weiner's laptop before announcing on Friday that the emails existed. The FBI eventually obtained a warrant over the weekend.

The FBI, investigating Weiner's inappropriate communication with underage girls, subpoenaed his laptop in late September. He shared the laptop with his estranged wife and top Clinton aide Huma Abedin, whose emails to and from Hillary Clinton are now being actively reviewed by the agency.

The Justice Department reportedly asked the FBI not to disclose the discovery of the emails to Congress so close to the November 8 election, but Comey wrote to his employees on Friday that he felt "an obligation to do so given that I testified repeatedly in recent months that our investigation was completed."

The FBI came under renewed fire on Tuesday after a mostly dormant Twitter account operated by the agency, "FBI Records Vault," suddenly started releasing records from a 15-year-old investigation into the Clinton Foundation that was closed in 2005.