A new FBI report says it was the bureau’s first investigation into Clinton’s use of a private email server while secretary of state.
The report is based on newly released emails the FBI said were made public on Wednesday.
It is the first time the FBI has publicly said that Clinton, who served as president from 2009 to 2013, used her private email address while in office.
The FBI said the new emails have been provided to Congress and will be released to the public in the coming days.
The emails were made available by the State Department, which has released them to the FBI.
Clinton and her allies say the new information shows she used the private server in a way that violated the law.
In the interim, the FBI is looking into whether she broke any laws or regulations.
A spokesman for Clinton said the newly released documents are the first step in an ongoing, independent investigation into the emails.
But they also offer an important window into what went on behind the scenes in the days before Clinton was sworn in as secretary of State, including what she knew about the existence of her email server and the circumstances around its destruction.
“While we do not have all the facts, the documents are consistent with the FBI’s view that the emails were mishandled and did not meet the standards required to be classified,” Brian Fallon, the bureau director, said in a statement.
The latest development is part of a process that has taken more than a year, after a judge approved the FBI request to examine the emails, according to a timeline provided by FBI officials.
The new emails also show that Clinton told FBI agents she would not have sent any classified information on her private account if she knew it would cause “public harm.”
Clinton told the bureau that she did not understand the legal implications of sending and receiving classified information while in the United States, but that it was “not my place to know.”
The FBI said she also said she was not aware of the need for a separate email account and did so in an effort to shield her personal email account from being hacked.
The documents also show the bureau was investigating whether Clinton lied to Congress about whether she did or did not use the private email account to conduct government business.
Clinton said during the presidential campaign that she had “never sent or received classified information,” but in fact she had been in touch with people about sensitive matters and was cleared by a senior State Department official.
She later said she did send classified information.
The State Department inspector general’s office, which was also looking into the matter, concluded in October that the State.gov email account Clinton used to conduct official business was secure, but did not recommend that the FBI reopen its investigation.
The bureau said it found that the use of the private account “was consistent with a standard practice of using personal email accounts for official business.”
The inspector general said Clinton “did not comply with State Department policies, procedures, or protocols” by using her private server to send and receive classified information and that she “failed to take steps to protect classified information.”
In a statement, Fallon said the bureau is reviewing the new documents and will make a recommendation to Congress in the near future.