This is according to an unnamed “intelligence source familiar with the FBI investigation.” This source says, “It is very harmful to her and increases the likelihood and pressure on [the Department of Justice] to indict. […] [The report] is not evidence in itself, but it clears up confusion [about] Department of State rules and makes the IG [inspector general] a witness, and the people they interviewed, to her computer antics being done without permission.”
The FBI would need to recommend an indictment before the Justice Department would decide to move forward with the case or not.
The source also says that the report “will be useful as rebuttal, potential evidence in 18 USC 1001 charges and establishing aspects of 18 USC 793.” “18 USC 1001” is a reference to a statute known as the “false statements statute.” “Materially false” statements given to a federal officer could result in five years in prison per violation. “18 USC 793” is a reference to a statute which is part of the Espionage Act, and is known as the “gross negligence” statute. (Fox News, 6/1/2016)