Special counsel Robert S. Mueller III departs after a meeting on Capitol Hill in Washington in June. (J. Scott Applewhite/AP)

An FBI official who was removed from special counsel Robert S. Mueller III's investigation into Russian meddling in the 2016 election over politically charged texts disparaging President Trump considered never joining the probe at all, because of a "gut sense and concern, there's no big 'there' there."

Peter Strzok, the former deputy head of counterintelligence at the FBI, expressed that opinion in texts h exchanged with FBI lawyer Lisa Page on May 19, 2017, and that were released Tuesday by Sen. Ron Johnson (R-Wis.), chairman of the Senate Homeland Security and Government Affairs Committee.

The release of the additional texts comes on the heels of a revelation that the FBI did not save five months' worth of texts between Strzok and Page beginning in mid-December 2016 and ending on the day that Mueller was appointed as special counsel. Lawmakers noticed that the texts were missing after receiving hundreds of pages of Page's and Strzok's text exchanges from the Justice Department late Friday.

Johnson joined Senate Judiciary Committee Chairman Charles E. Grassley (R-Iowa) on Tuesday to demand a reckoning from the Justice Department's inspector general for why Congress was not notified the texts were missing. In a letter to Inspector General Michael Horowitz, Johnson and Grassley also asked Horowitz to explain by Monday what steps were being taken to locate the missing texts, or explain the circumstances that led to their disappearance.

The texts that Johnson published Tuesday detail a conversation between Page and Strzok about whether they should attempt to join Mueller's probe. In one message, Strzok appears to wonder whether the Trump probe could be an "investigation leading to impeachment" before guessing that "the odds are nothing" would result from the case.

He also texted Page that he felt "a sense of unfinished business" over having "unleashed" the investigation into Hillary Clinton's emails.

"Now I need to fix it and finish it," he added.

Over the course of the texts, Page — who was also considering whether she should join Mueller's probe — told Strzok that he "shouldn't take this on" and that "we can't work closely on another case again." Page and Strzok were having an affair during the period they were exchanging the messages in question, according to people familiar with the matter.