The Justice Department's office of inspector general is said to be probing former Attorney General Loretta Lynch's role in the FBI's investigation of Hillary Clinton's handling of emails as Secretary of State.

The DoJ watchdog's probe was revealed Saturday by House oversight committee chairman Jason Chaffetz in an interview with Fox & Friends, and joins a Senate Judiciary Committee inquiry into Lynch.

Chaffetz, a Republican representative from Utah, said DoJ Inspector General Michael Horowitz 'has been diving into this' and is expected to release a report on Lynch's oversight of the now-closed FBI investigations in 'the first part of next year.'

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House oversight committee chairman Jason Chaffetz (pictured) said Saturday that DoJ Inspector General Michael Horowitz is investigating Lynch's role in Clinton email probe

Loretta Lynch led the Justice Department as attorney general while the FBI was investigating Clinton's use of a private email server as Secretary of State

Clinton, who was at the time the Democratic presidential nominee, was let off the hook for the classified materials the FBI investigation found on her private email server

Lynch led the Justice Department as attorney general while the FBI was investigating Clinton's use of a private email server as Secretary of State, and Republicans have raised fears that Lynch interfered in the investigations.

Those fears reached a peak after Bill Clinton spoke privately with Lynch on the tarmac of a Phoenix airport last summer, sparking concern that he appealed to her for help quashing the investigation.

Lynch's potential role in the email investigation resurfaced on May 3, when former FBI Director James Comey told Congress that Lynch instructed him to call the investigation a 'matter' in public comments, mirroring the Hillary Clinton presidential campaign's language.

Comey also hinted that he took the extraordinary step last July of speaking out about the email investigation because of fears over interference into the probe by Justice Department leadership.

Former FBI Director James Comey told Congress on May 3 that Lynch instructed him to call the Clinton email investigation a 'matter' in public comments

'A number things had gone on, some of which I cannot talk about yet,' Comey said, 'that made me worry that the Department leadership could not credibly complete the investigation and decline prosecution without grievous damage to the American people's confidence in the justice system.'

In April, the New York Times reported a memo 'written by a Democratic operative who expressed confidence that Ms. Lynch would keep the Clinton investigation from going too far.'

That document, the Times reported, was recovered from Russian hackers who were unaware the FBI could see what they had taken from U.S. networks.

The Department of Justice inspector general's probe into Lynch has not been confirmed, and Horowitz was not reachable for comment on Sunday.