Grassley said Wednesday it was a "foregone conclusion" the judiciary committee would hold a hearing on the Comey memos and the FBI Russia investigation.
That may mean Chaffetz's last major role in Congress is looking into whether President Donald Trump tried to interfere in an FBI investigation.
Two Senate committees are seeking memos former FBI Director James Comey wrote related to whether President Donald Trump asked him to end an investigation into former national security adviser Michael Flynn.
Later, the Senate judiciary committee whose subcommittee is also investigating Russian meddling into the USA election, requested that the FBI "provide all memos relating to former FBI Director Comey's interactions with his superiors in both the Trump and Obama administrations", according to a statement.
For one, "18 USC 1001 sets forth that a felony is committed by anyone who in any matter with the jurisdiction of the executive, legislative or judicial branch of the government of the United States knowingly and willfully 1) falsifies, conceals, or covers up by any trick, scheme or device a material fact, 2) makes any materially false, fictitious or fraudulent statement or representations or 3) makes or uses any false writing or document knowing the same to contain any materially false, fictitious, or fraudulent statement or entry", Cummings wrote.
Comey had testified exactly 10 years ago in the Senate about his famous hospital-room showdown with former U.S. President George W. Bush's White House aides at John Ashcroft's bedside, CNN reported.More news: Dirk Kuyt scores the most important goals of Feyenoord's season
The letter came after the Senate Intelligence Committee made a similar request for Comey's memos. "At worst, he has obstructed justice".
The requests came a day after the New York Times published a report, subsequently corroborated by other outlets, detailing the existence of a memo written by Comey describing a meeting in which Trump asked him to drop an investigation into the Russian Federation ties of his sacked national security adviser Michael Flynn.
"The President has the utmost respect for our law enforcement agencies, and all investigations".
On Wednesday evening, shortly after the Justice Department's announcement that it had selected former FBI Director Robert Mueller as a special counsel to oversee investigations into possible ties between the Trump campaign and Russia, Chaffetz told Fox News that he was not convinced a special counsel was necessary.
The main reason for firing James Comey was the Federal Bureau of Investigation being "in turmoil", Trump said, branding the former intelligence chief a "showboat".