The report examined actions taken by Comey and other officials before the 2016 presidential election, including Clinton's use of a personal email server while she was Secretary of State under President Barack Obama.
Deputy Attorney General Rod Rosenstein was spotted entering the West Wing on Thursday.
The specific email in which Strzok talks of stopping Trump, Horowitz explains, "caused us to question the earlier Midyear investigative decisions in which he was involved, and whether he took specific actions in the Midyear investigation based on his political views".
In another tweet, the Democratic senator wrote: "I'm calling it now: no matter what the DOJ IG report actually says, President Trump's sycophantic supporters will try to claim that somehow he is the victim of Federal Bureau of Investigation wrongdoing & bias". In an op-ed published in the New York Times, Comey said the report confirmed the call there was "no prosecutable case" against Clinton, and stood by his decision to inform Congress in that the case had been reopened days before the election.
"Now that I am back from Singapore, where we had a great result with respect to North Korea, the thought process must sadly go back to the Witch Hunt, always remembering that there was No Collusion and No Obstruction of the fabricated No Crime", the president wrote.
The report from Inspector General Michael Horowitz concluded that the prosecutorial decisions in the Clinton case were "consistent" and not affected by bias or other improper actions. "No he's not. We'll stop it". Lawmakers on Capitol Hill also will get briefings ahead of the report's public release, aides said.
Concerned about the "appearance that former President Clinton was influencing" the probe, Lynch began talking to her staff the next morning about possibly recusing herself from overseeing the investigation, according to the report.
At a congressional hearing last May, he said he was concerned that the Justice Department could not "credibly" announce the conclusion of its investigation, in part because Lynch had met aboard her plane with former US President Bill Clinton.
The president has previously pointed to text message exchanges between FBI lawyer Lisa Page and FBI agent Peter Strzok that included insults directed at Trump as evidence that both the investigation into his campaign's potential ties to Russian Federation and the outcome of the Hillary Clinton email investigation were tainted.
"It is a damning indictment of former FBI Director Comey and the Department of Justice's mishandling of the investigation", said Rep Darrell Issa, a California Republican.
Horowitz also criticized Comey for announcing that the probe was reopening days before the election, before following up days later to once again say it was closed and that no new evidence emerged that would warrant prosecuting the former first lady. Strzok and Page, who were having an affair with one another, exchanged a series of barbed anti-Trump text messages and emails. "Second, this report is vital in shedding light for future leaders on the nature and quality of our investigation and the decisions we made".
One example cited in the new report is an email exchange between Strzok and Page on August 8, 2016. But the blows are glancing at best - a far cry from the April inspector general report that alleged McCabe misled investigators exploring a media leak.
Democrats said the report shows "that the FBI's actions helped Donald Trump become President".