(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.

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