Former FBI Deputy Director Andrew McCabe knew of thousands of emails related to the Hillary Clinton private server investigation for at least a month before then-FBI Director James Comey informed Congress, The Wall Street Journal reported late Wednesday.

That lag is the subject of an investigation by Justice Department Inspector General Michael Horowitz as part of a wider probe into the FBI's actions prior to the 2016 election. The Washington Post was the first to report that McCabe was a focus of Horowitz's investigation.

The timeline of when the emails were discovered on the laptop of former Democratic Rep. Anthony Weiner emerged in text messages between FBI officials Peter Strzok and Lisa Page, the Journal reported.

McCabe left his position Monday ahead of his planned retirement, effective March 18. The Post reported Tuesday that McCabe had met with FBI Director Christopher Wray to discuss the inspector general's investigation prior to the announcement of his departure.

On Sept. 28, Strzok messaged Page that he had been "called up to Andy's office" earlier that day and told of "hundreds of thousands of emails turned over by Weiner’s [attorney] to sdny," a reference to the U.S. Attorney's Office for the Southern District of New York. Strzok added that the email cache "includes a ton of material from spouse," a reference to Weiner's then-wife Huma Abedin, a top adviser to Clinton.

However, the existence of the emails on Weiner's laptop was not made public until Oct. 28, when Comey informed Congress in a letter that the FBI was re-opening the Clinton investigation.

Strzok and two other agents spent the weekend before the Nov. 8 election sifting through about 3,000 emails from Weiner's laptop, the Journal reported. Early on the morning of Sunday, Nov. 6, Strzok texted Page that the team had found "no new classified" emails.

That same day, Comey informed Congress that the Weiner emails had not altered the FBI's initial decision not to prosecute Clinton.

At the time, the U.S. Attorney's office was investigating Weiner for crimes related to explicit messages he sent to a teenage girl. Weiner pleaded guilty to a charge of transferring obscene material to a minor and was sentenced to 21 months in prison.

The conservative group Judicial Watch has claimed that at least 18 emails containing classified information were found on Weiner's laptop. Among them were emails from Abedin's "clintonemail.com" account as well as from her Blackberry. Comey told lawmakers earlier this year that he believes Abedin regularly forwarded emails to Weiner for him to print out so she could give them to Clinton.

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