House Intelligence Committee Chairman Adam Schiff (D-Calif.) declined a request by Republicans for Hunter Biden and the anonymous whistleblower to testify in the public impeachment inquiry hearings beginning next week.

“This inquiry is not and will not serve, however, as a vehicle to undertake the same sham investigations into the Bidens or 2016 that the President pressed Ukraine to conduct for his personal political benefit, or facilitate the President’s effort to threaten, intimidate, and retaliate against the whistleblower who courageously raised the initial alarm,” Schiff said in a letter to Intelligence Committee Ranking Member Devin Nunes (R-Calif.).

Echoing his prior claim that the whistleblower testimony is no longer necessary, Schiff said other witnesses and documents do “not only confirm but far exceed the initial information in the whistleblower’s complaint.”

The whistleblower complaint, which is the pivotal point in the Democrats’ ongoing impeachment inquiry, alleged that President Donald Trump urged Ukrainian President Volodymyr Zelenskiy to investigate former Vice President Joe Biden and his son’s dealing in Ukraine in exchange for military aid. 

Joe Biden was tapped as the leading role in carrying out U.S.policy in Ukraine, as his son Hunter Biden served on the board of a natural gas firm Burisma Holdings that allegedly paid him a minimum of $50,000 per month. Joe Biden was videotaped telling how he pressured former Ukrainian President Petro Poroshenko to fire their top prosecutor, Viktor Shokin who was investigating the gas company.

State Department official George Kent, who testified behind closed doors before committees, told congressional investigators that he raised concerns about Hunter Biden’s role one the board of Burisma Holdings in 2015, but was rejected by Joe Biden’s staff. 

Republicans also called for Hunter Biden’s longtime business partner, Devon Archer, who also sat on the board of the Ukrainian gas firm to testify publicly, arguing that Archer could provide more information on “the nature and extent of Ukraine’s pervasive corruption information that bears directly on President Trump’s long-standing and deeply held skepticism of the country.”

“While in traditional hearings the minority is permitted to call witnesses, the resolution only allows minority members to suggest a witness list and requires them to provide ‘a detailed written justification of the relevance of the testimony of each requested witness.’ … Your failure to fulfill minority witness requests shall constitute evidence of your denial of fundamental fairness and due process,” Nunes wrote in the letter to Schiff. 

President Trump took to Twitter earlier Saturday, saying that House Speaker Nancy Pelosi (D-Calif.), Schiff, and Biden should be added to the list of witnesses.

“I recommend that Nervous Nancy Pelosi (who backed up Schiff’s lie), Shifty Adam Schiff, Sleepy Joe Biden, the Whistleblower (who miraculously disappeared after I released the transcript of the call), the 2nd Whistleblower (who also disappeared), & the I.G., be part of the list!” the president tweeted.