House Republicans are probing the Department of Justice (DOJ) about possible retaliation against whistleblowers connected to its impeachment inquiry into President Joe Biden, letters obtained by the Daily Caller Tuesday reveal.

Judiciary Committee Chairman Jim Jordan, Oversight Committee Chairman James Comer and Ways and Means Committee Chairman Jason Smith addressed letters to Attorney General Merrick Garland, Special Counsel David Wiess and U.S. Commissioner of Internal Revenue Daniel Werfel on Tuesday, asking about potential retaliation against the whistleblowers.

The letters claim that Hunter Biden, the president’s son and a key character in the impeachment inquiry, and his lawyers launched an intimidation campaign against the whistleblowers. The lawmakers demanded that the DOJ tell their respective committees if they are investigating the subjects.

“Retaliation against whistleblowers is unlawful and morally repugnant, and if the Biden administration is doing that to these whistleblowers, there will be hell to pay,” a GOP source with knowledge of the investigation told the Daily Caller in a statement.

The lawmakers continued to ask the DOJ to provide their respective committees with documents and communications relating to an investigation into the whistleblowers, the letter shows. Providing such, the lawmakers state, will ensure that the DOJ is not retaliating against the whistleblowers.

“The Committees will not tolerate any retaliatory conduct by the Department against these or any other whistleblowers. Whistleblowers play an integral role in identifying and rooting out waste, fraud, abuse, mismanagement, and corruption within federal agencies. Federal law protects whistleblowers from retaliation,” the letter addressed to Garland wrote.

“Any efforts, including those by the Department, to investigate whistleblowers for making lawful disclosures raise serious concerns about the continued weaponization of the federal government. Any and all attempts to intimidate or retaliate against Mr. Shapley and Mr. Ziegler for their protected disclosures to Congress must stop,” the letter continued.

As a part of the impeachment inquiry into President Biden, Congress held a closed-door deposition with Hunter Biden to ask him questions about his foreign business dealings. The first son was unable to recall details about his foreign business dealings at least 29 times during his deposition, though he maintained that he could remember one thing: that his father was not involved. (RELATED: Here’s All The Evidence Connecting Joe Biden To Hunter Biden’s Foreign Business Dealings)

“I am here today to provide the committees with the one uncontestable fact that should end the false premise of this inquiry: I did not involve my father in my business, not while I was a practicing lawyer, not in my investments or transactions, domestic or international, not as a board member, and not as an artist, never,” Hunter Biden said in his opening statement before going on to note that he “did not recall” information about certain business meetings.