(CNN) - The Department of Justice Inspector General's report on the start of FBI's investigation into Russian interference in the 2016 election will say the probe was properly launched but lower-level employees made a series of mistakes, according to two sources familiar with the matter.
The investigation on the effort to obtain warrants under the Foreign Intelligence Surveillance Act on Carter Page, a former foreign policy adviser to the Trump campaign, is expected to conclude that the FBI's Crossfire Hurricane investigation was properly predicated, and that there were a series of mistakes and improper handling of the Page FISA application by lower-level employees.
The New York Times was first to report on the expected conclusion of the report.
The report is also expected to conclude that Page was appropriately targeted for surveillance and that the FBI appropriately disassociated itself from Christopher Steele, the former British spy and author of the infamous "Steele Dossier" about President Donald Trump, after leaks and contacts with the media were uncovered.
CNN first reported that a former FBI lawyer is under criminal investigation after allegedly altering a document related to the 2016 surveillance of Page.
People familiar with the report told the Times that while it characterizes the pursuit of the FISA request as careless and slapdash, the report discredits major conspiracy theories that Trump has advanced about the investigation -- finding, for example, that the FBI met the legal evidence threshold to open the probe.
Notably, the people said that Justice Department Inspector General Michael Horowitz did not find evidence of politically motivated actions by former FBI Director Jim Comey, subsequent acting Director Andrew McCabe -- now a CNN analyst -- or former senior official Peter Strzok, who was removed from special counsel Robert Mueller's team after an internal investigation revealed text exchanges that could be read as exhibiting political bias.
The paper reported that Horowitz identified the lawyer under criminal investigation as one of a small group of FBI officials who sent texts disparaging Trump, prompting him to depart the investigation in February 2018. After being interviewed by the inspector general's office, the lawyer resigned from the FBI in September, according to the Times.
The people told the paper that the lawyer made additions to an email from an official at a different federal agency containing multiple factual assertions -- such that the lawyer's own assessment looked like an additional assertion.
That modified email was included in the lawyer's briefing for another FBI official to read before signing a court affidavit asserting the evidence supplied for the FISA application, and contains details that will remain classified upon the report's release, the Times reported.
The forthcoming report also determines that Joseph Mifsud, a Malta-born professor referenced in Mueller's report, was not an FBI informant, the people told the Times.
Mifsud allegedly told Trump campaign adviser George Papadopoulos that Russia had damaging emails on 2016 Democratic presidential candidate Hillary Clinton -- an event that factored in to opening the investigation.
Papadopoulos and right-wing pundits have suggested that Mifsud was working for the FBI when he discussed Clinton's emails with Papadopoulos, and that the conversation was a setup by the FBI to entrap the Trump campaign. There is no evidence supporting those discredited theories, which is also undermined by the new watchdog report.