The FBI did not retain text messages exchanged by two senior officials involved in the probes of Hillary Clinton and Donald Trump for a five-month period ending the day a special counsel was appointed to investigate possible connections between the Trump campaign and Russia, according to a new congressional letter.

The letter from Sen. Ron Johnson (R-Wis.), chairman of the Senate Homeland Security and Government Affairs Committee, to FBI Director Christopher A. Wray indicates the Justice Department has turned over to lawmakers a new batch of texts from senior FBI agent Peter Strzok and FBI lawyer Lisa Page. The messages have not been made public.

As The Washington Post reported in December, Strzok was removed from the Trump probe after internal investigators discovered he and Page, who were romantically involved , exchanged anti-Trump, pro-Clinton texts during investigations of both presidential candidates. Later that month, the Justice Department provided Congress with hundreds of pages of messages. Republicans said the texts revealed political bias at the bureau's highest levels.

Johnson's weekend letter said his committee received 384 pages of new Strzok-Page texts late Friday. The lawmaker is asking the FBI to explain in more detail why it "did not preserve text messages between Ms. Page and Mr. Strzok between approximately December 14, 2016 and May 17, 2017.''

Top FBI official assigned to Mueller’s Russia probe said to have been removed after sending anti-Trump texts (The Washington Post)

May 17 is a key date in the Russia probe: It's the day Deputy Attorney General Rod J. Rosenstein tapped Robert S. Mueller III as a special counsel to take over the investigation.

An FBI spokesman declined to comment.

Much occurred during the months the Strzok-Page texts were not retained. Then-FBI Director James B. Comey met repeatedly with President Trump, the Russia probe intensified and began to focus on former national security adviser Michael Flynn and, in early May, Trump fired Comey.

The FBI previously informed the Justice Department that "many FBI-provided Samsung 5 mobile devices did not capture or store text messages due to misconfiguration issues related to rollouts, provisioning and software upgrades that conflicted with the FBI's collection capabilities," a Justice Department official told lawmakers in an earlier letter. As a result, it says, "data that should have been automatically collected and retained for long-term storage and retrieval was not collected.''

Strzok's and Page's conduct are the subject of an investigation by the Justice Department's inspector general. Strzok was removed from Mueller's team in July when Mueller was notified of the texts. Page left the team two weeks earlier for what officials have said were unrelated reasons.

Strzok's lawyer declined to comment. A lawyer for Page did not immediately comment.

Johnson's letter quotes from a handful of the newly revealed text messages, including one from July 1, 2016, in which Page expresses disdain for then-Attorney General Loretta E. Lynch, who had just announced she would accept the charging recommendations of career officials in the probe of Clinton's use of a private email server while she was secretary of state. Lynch made that decision after she came under fire for meeting with former president Bill Clinton on the tarmac of an airport in Phoenix.

"Yeah, it's a real profile in courag(e), since she knows no charges will be brought,'' Page texted to Strzok.

By that point, multiple news outlets had reported charges were not likely to be filed in the Clinton case. Days later, Clinton was formally interviewed by the FBI, and Comey announced in a news conference on July 5, 2016, he would not be recommending any criminal charges in the case.

The new texts also indicate Strzok and Page occasionally emailed each other using private accounts, rather than government ones, according to the letter, though one of those texts suggests that may have been unintentional.