• Hunter Biden said he would testify before Congress next month as part of a Republican-led investigation into President Joe Biden and his family.
• House Oversight Chairman James Comer, R-Ky., subpoenaed the president's son and brother as part of an impeachment inquiry into the president.
• Hunter Biden agreed to appear before the House Oversight Committee on Dec. 13 or on another date in December.

Hunter Biden said Tuesday he would testify before Congress in December, as part of a Republican-led impeachment investigation into President Joe Biden and his family.

"Your empty investigation has gone on too long wasting too many better-used resources. It should come to an end," Hunter Biden's attorney Abbe Lowell wrote in a letter to the chairman of the House Oversight Committee.

"Consequently, Mr. Biden will appear at such a public hearing on the date you noticed, December 13, or any date in December that we can arrange," wrote Lowell.

The defiant letter came weeks after House Oversight Chairman James Comer, R-Ky., subpoenaed the president's son and brother to sit for closed-door depositions, as he conducts an impeachment inquiry into the Democratic president.

Comer later Tuesday appeared to reject Hunter Biden's proposal for a public hearing on Dec. 13 — but left the door open for him to testify before Congress at a later date.

"Hunter Biden is trying to play by his own rules instead of following the rules required of everyone else," Comer said in a statement. "That won't stand with House Republicans. Our lawfully issued subpoena to Hunter Biden requires him to appear for a deposition on December 13."

"We expect full cooperation with our subpoena for a deposition," Comer said, adding that investigators "also agree that Hunter Biden should have opportunity to testify in a public setting at a future date."

Comer and other Republicans accuse the president of being involved in, and profiting from, influence-peddling schemes devised by his family members, intended to enrich one another by virtue of their ties to a powerful politician.

The White House has roundly denied any wrongdoing by the president. Democrats have blasted the impeachment efforts as a political fishing expedition.

"Your Committee has been working for almost a year—without success—to tie our client's business activities to his father," Lowell wrote in Tuesday's letter.

He accused Comer of hypocrisy, for claiming that he wants to probe potential conflicts of interest surrounding the business activities of a president's family, while "turning a blind eye toward former President Trump and his family's businesses."

"Unlike members of the Trump family, Hunter is a private person who has never worked in any family business nor ever served in the White House or in any public office," wrote Lowell.

"Notwithstanding this stark difference, you have manipulated Hunter's legitimate business dealings and his times of terrible addiction into a politically motivated basis for hearings to accuse his father of some wrongdoing," Lowell wrote.

Lowell said they were offering Comer a public hearing with Hunter Biden, instead of a deposition behind closed doors, because, "We have seen you use closed-door sessions to manipulate, even distort the facts and misinform the public."

"We therefore propose opening the door," he wrote.