Two leaders of the conservative House Freedom Caucus want the Justice Department’s internal watchdog to investigate whether Deputy Attorney General Rod J. Rosenstein threatened congressional aides in a January meeting.

Rep. Mark Meadows (R-N.C.), the group’s chairman, and Rep. Jim Jordan (R-Ohio), a co-founder and influential conservative leader, made the request of Inspector General Michael E. Horowitz on Monday, according to a letter obtained by The Washington Post.

“This notion Mr. Rosenstein threatened to use his official investigative powers as Deputy Attorney General to retaliate against rank-and-file staff members for sending written oversight requests raises concerns he has abused his authority in the context of this investigation,” they wrote.

The call for a probe comes as President Trump’s defenders in Congress have turned up the heat on the Justice Department and the FBI over their probes into the 2016 presidential candidates — culminating last week in a fiery hearing where Republicans berated senior FBI official Peter Strzok for sending text messages during the campaign criticizing and denigrating then-candidate Trump.

The House hearing with FBI agent Peter Strzok devolved into personal attacks, partisan exchanges and a perjury accusation. Here's a look at the biggest moments. (Jenny Starrs/The Washington Post)

The letter requesting the investigation into Rosenstein’s behavior comes on the same day Trump questioned the findings of U.S. law enforcement and intelligence agencies that Russia interfered in the 2016 election. Rosenstein is overseeing the pending investigation led by special counsel Robert S. Mueller III probing the interference and allegations, yet to be proved, that Trump’s campaign colluded with that effort.

Members of the Freedom Caucus, particularly Jordan and Meadows, have been among the most persistent critics of the Justice Department’s handling of the 2016 campaign probes, and now the special counsel investigation. They have amped up their focus on Rosenstein, who appointed Mueller after Attorney General Jeff Sessions recused himself from Russia-related matters last year. Only Rosenstein can dismiss Mueller for cause, though as a presidential appointee, Rosenstein can be removed by Trump.

Some of the group’s members have floated the idea of impeaching Rosenstein over what they call a lack of transparency and cooperation with House Republican investigators. Meadows acknowledged in late April that he had been involved in drafting articles of impeachment as a “last resort” if the Justice Department did not cough up relevant documents.

Deputy Attorney General Rod J. Rosenstein has been the target of President Trump's ire for months. Here's a look back at their history. (Jenny Starrs, Monica Akhtar/The Washington Post)

On Friday, chatter arose that the House conservatives might actually file the resolution after Meadows was seen off the House floor holding a red file folder containing a piece of legislation he refused to describe to reporters. Asked then if it was a resolution to impeach Rosenstein, he said, “Certainly there are concerns about the Department of Justice and the FBI.”

The letter delivered Monday appears to have delayed any impeachment effort for the time being, according to a Republican familiar with the conservatives’ plans but not authorized to discuss them publicly.

Meadows, in a brief interview Monday, declined to discuss a potential impeachment resolution.

Rosenstein’s alleged threats in the January meeting, delivered to Republican staff members for the House Permanent Select Committee on Intelligence, were first reported by Fox News last month and quickly gained traction in conservative circles. The initial story reported that the threats came in retaliation for committee oversight requests, with the Justice Department disputing the essential claims in the story.

During a House Judiciary Committee hearing last month, Jordan questioned Rosenstein about the episode, citing “media reports” that indicated he had threatened Intelligence Committee staffers: “Did you threaten to subpoena their calls and emails?” he asked.

Rosenstein flatly denied making any threats, and he seemed to mock Jordan in his reply: “No, sir, and there’s no way to subpoena phone calls,” he said, adding, “I would suggest that you not rely on what the press says, sir.”

Jordan indicated he was not satisfied with the denial: “Who are we supposed to believe?” he asked. “Staff members who we’ve worked with, who have never misled us? Or you guys, who we’ve caught hiding information from us, who tell a witness not to answer our questions, who are we supposed to believe?”

Said Rosenstein, “You should believe me because I’m telling the truth and I’m under oath. And, if you want to put somebody else under oath, and they have something different to say, I’d be happy to respond.”

Later in the hearing, Rosenstein said that several other federal law enforcement officials were in the room with him at the time, including FBI Director Christopher Wray, implying that they would back his account.

Representatives for the Justice Department and for Horowitz declined to comment on the letter Monday.

Horowitz has spent months examining the Justice Department’s conduct during the 2016 election, issuing a report last month that blasted former FBI director James B. Comey as well as Strzok for their behavior during the 2016 probe into Democratic presidential candidate Hillary Clinton’s email practices. He is now  in the middle of a similar review of the Russia probe.

Matt Zapotosky contributed to this report.