The surprise tweet from a little-used FBI account came about 1 p.m. Tuesday, announcing that the agency had published on its website 129 pages of internal documents related to a years-old investigation into former president Bill Clinton's pardon of a fugitive Democratic donor.

William J. Clinton Foundation: This initial release consists of material from the FBI's files related to the Will... https://t.co/Y4nz3aRSmG — FBI Records Vault (@FBIRecordsVault) November 1, 2016

The seemingly random reminder of one of the darkest chapters of the Clinton presidency a week before the election drew an immediate rebuke from Hillary Clinton's campaign - with its spokesman tweeting that the FBI's move was "odd" and asking whether the agency planned to publish unflattering records about Republican candidate Donald Trump.

"Will FBI be posting docs on Trump's housing discrimination in '70s?" asked Brian Fallon.

Absent a FOIA litigation deadline, this is odd.

Will FBI be posting docs on Trump's housing discrimination in '70s?https://t.co/uJMMzX6rtI — Brian Fallon (@brianefallon) November 1, 2016

For the second time in five days, the FBI had moved exactly to the place the nation's chief law enforcement agency usually strives to avoid: smack in the middle of partisan fighting over a national election, just days before the vote.

The publication of the files related to the Marc Rich pardon inquiry, which an agency official said was done in response to pending public records requests, came as the Clinton campaign and Democratic lawmakers continued to fume over FBI Director James Comey's decision with less than two weeks before the election to announce that he was effectively resuming a review of Hillary Clinton's email practices.

Comey's move to direct agents to suddenly review thousands of emails discovered as part of a separate inquiry into former congressman Anthony Weiner, D-New York, has led to a range of criticism of the FBI, with Democrats and some Republican lawmakers questioning whether Comey violated Justice Department policies by making a decision that risked shaking up a political campaign.

Some Democrats have also accused Comey of hypocrisy, citing reports this week that the director argued internally last month that it was too close to Election Day to publicly accuse Russia of meddling in the race. Top intelligence officials issued a rare statement implicating Russia in hacks of Democratic officials and party offices, but Clinton and have aides have gone further, alleging that Russian President Vladimir Putin is trying to tilt the race in Trump's favor.

All told, the events of the past week have dragged the FBI, a highly regarded institution whose leaders have in recent years worked to build a reputation for impartiality, into the thicket of the polarized presidential race.

"Americans now look at the FBI and see a political entity, not a nonpartisan entity - and that has huge ramifications for the FBI and for all of us," said Matt Miller, former chief spokesman for the Justice Department and a Clinton supporter. "It sows disbelief in our system of government and is hugely toxic."

On Tuesday, FBI investigators were starting to examine the newly discovered emails and trying to discern how they ended up on a computer owned by Weiner. As of Tuesdaymorning, an official said, investigators had found no sign that the computer contained "new and bigger" evidence about Clinton. But the official said the FBI was deploying "all computers, all hands on deck" to sort through the high volume of emails and that "no one knows" what the emails contain.

FBI officials did not respond to questions about the agency's role in the campaign.

FBI Director James Comey testifies on Capitol Hill in Washington before the House Oversight Committee to explain his agency's recommendation to not prosecute Hillary Clinton. (J. Scott Applewhite / AP Photo)

As for the release of the Rich files days before the election, FBI officials said the timing was coincidental. The FBI released a statement saying that they were published after Freedom of Information Act requests and were posted "automatically and electronically to the FBI's public reading room in accordance with the law and established procedures." This happens, the statement said, on a "first-in, first-out" basis.

The events of the past week have created an unusual political storm around Comey, who until this election year had generally drawn praise from leaders of both parties. When he announced in July that he believed that "no reasonable prosecutor" would charge Clinton for mishandling classified information through her use of a private email server, Democrats called him fair-minded while some Republicans, including Trump, accused him of being part of a rigged system. This week, the roles have been reversed.

Rep. Trey Gowdy, R-South Carolina, who led the House investigation of the attacks on the U.S. diplomatic posts in Benghazi, Libya, said Tuesday that Democrats are improperly blaming Comey for a sequence of events that began with Clinton's decision as secretary of state to use a private server. "Secretary Clinton is the reason why you and I are having this conversation, not Jim Comey," he told CNN.

The Twitter account used to publicize the Rich files, an official FBI account called @FBIRecordsVault, had been dormant for more than a year until Sunday, when it began to tweet links to archived documents.

They included records related to Fred Trump, the father of the GOP nominee, which were posted to the website in early October. Those records included eight pages of largely biographical details about the elder Trump, much of which appeared to be compiled by the FBI in 1988. The agency advertised the Trump records by tweeting: "Fred C. Trump (1905-1999) was a real estate developer and philanthropist."

Fred C. Trump: Fred C. Trump (1905-1999) was a real estate developer and philanthropist. This release consists of... https://t.co/21KgtPpmzk — FBI Records Vault (@FBIRecordsVault) October 30, 2016

Another tweet linked to previously released internal investigative notes from the FBI's probe of Clinton's private email server.

Hillary R. Clinton: Hillary Rodham Clinton served as U.S. Secretary of State from January 21, 2009 to February 1,... https://t.co/9e7TYx2GVQ — FBI Records Vault (@FBIRecordsVault) October 30, 2016

The Rich documents provided little new information about the matter, which plagued the first years of Bill Clinton's post-presidency. But they served as a reminder of the vigor of the criminal probe into the matter.

Rich, who received his pardon on Bill Clinton's last day in the White House, had fled to Switzerland after learning he would be indicted on a charge of tax evasion in the 1980s. The investigation, conducted between 2001 and 2005, was disclosed in news accounts at the time and looked at whether Clinton had issued the pardon in exchange for political donations, including to Hillary Clinton's 2000 Senate race and to to the Clinton Foundation. It was closed with no charges.

The newly disclosed documents show the FBI internally referred to the matter as a "sensitive investigation concerning possible public corruption surrounding the pardons granted by former president William Clinton."

This week's release of the Rich files demonstrates how many of the players in the current Hillary Clinton drama played roles in Clinton-related battles of the past.

Comey, for instance, as a young prosecutor in New York, helped lead the case against Rich. Later, as U.S. attorney, he led the office that handled the investigation into the Clinton pardon from early 2002 to the end of 2003.

Former attorney general Eric Holder Jr., a Clinton backer who this week wrote in a Washington Post op-ed that Comey made a "serious error" in resuming the email probe, was deputy attorney general at the time of the pardon and acknowledged that he had been contacted directly by Rich's attorney. The pardon was criticized in part for bypassing an established process in which Justice lawyers review applications for merit. Holder's name was one of only a few not blacked out in the redacted files released this week.

Comey eventually supported Holder's nomination for attorney general but told senators in 2008 that he had been "stunned" by the Rich pardon and that Holder's actions in the case reflected a "huge misjudgment."

The release of the Rich files came as Democrats had been expressing their anger over Comey's handling of their suspicions of Russian meddling. For months, Democrats have been talking about alleged ties that Trump and his team have to Russia, and they have been encouraging the FBI to investigate the claims - in addition to the ongoing inquiry in to how Russian hackers broke in to the Democratic National Committee and the private email accounts of top party officials.

On Sunday, Senate Minority Leader Harry Reid, D-Nevada, said Comey possessed "explosive information about close ties and coordination between Donald Trump, his top advisors, and the Russian government." In a letter to Comey, Reid suggested that the FBI director may have violated a federal statute, the Hatch Act, that prohibits government officials from engaging in activities that can influence an election.

"Through your partisan actions, you may have broken the law," Reid wrote.

When asked about Reid's letter, a White House spokesman bluntly declined to back up his claims and concerns.

Press secretary Josh Earnest told reporters that President Barack Obama's administration would "neither defend nor criticize" Comey, and that the White House had received no FBI briefings "on even the existence of any investigation into the activities or habits of the Republican nominee."

Reid was briefed privately in August about the Russia threat by one of the country's top intelligence officials and came away "deeply shaken," according to an aide who was traveling with him at the time. During the private session, conducted in a specially secured briefing room at the FBI's Las Vegas office, Reid told aides he received disturbing details of Russian efforts to influence the election - and about possible Trump campaign ties to the Kremlin.

Afterward, he wrote Comey urging the FBI director to publicly investigate "a series of disturbing reports" indicating that Russia was trying "to influence the Trump campaign and manipulate it as a vehicle for advancing the interests of Russian President Vladimir Putin."

Trump, who has called Putin a "strong leader," has denied any connections to Russia.

But the FBI's approach to the questions has frustrated Democrats. Rep. Elijah Cummings (Maryland), the ranking Democrat on the House Oversight Committee, said Comey's decision to speak out on the Clinton emails while choosing to remain silent on Russia "raises serious questions about a very disturbing double standard."

Clinton campaign manager, Robby Mook, said it was "nothing short of jaw-dropping" that Comey would "show more discretion in a matter concerning a foreign-state actor than one involving the Democratic nominee for president."

By Rosalind S. Helderman, Tom Hamburger and Sari Horwitz, The Washington Post

Matt Zapotosky, Karoun Demirjian, Alice Crites, Ellen Nakashima and Bob Woodward contributed to this report.

Posted by Hannah Wise, breaking news reporter.