House investigators have asked Secretary of State Antony Blinken to turn over information on “sudden foreign policy decisions” by then-Vice President Joe Biden related to the firing of Ukrainian Prosecutor General Viktor Shokin.

In a letter sent Tuesday to Mr. Blinken, House lawmakers lay out a timeline of events that suggests Mr. Biden turned against Mr. Shokin after his son took a $1 million annual salary on the board of Ukrainian energy firm Burisma Holdings, which Mr. Shokin was investigating. 

Mr. Shokin was ousted on March 29, 2016, at the urging of Mr. Biden, who boasted in 2018 that he threatened to withhold $1 billion in U.S. loan guarantees to Ukraine unless Mr. Shokin was fired. 

In the letter, House Oversight and Accountability Chairman James Comer said the panel wants information from the State Department “to provide context for certain sudden foreign policy changes that occurred while Joe Biden was vice president, particularly regarding Ukraine while then-Vice President Biden’s son served on the board of directors  of a company being investigated for corruption.”

Mr. Comer’s letter was sent as House Speaker Kevin McCarthy announced plans to launch an impeachment inquiry into Mr. Biden over allegations of influence peddling related to his son’s foreign business deals, including his role on the Burisma board and the firing of Mr. Shokin. 

The impeachment inquiry, Mr. McCarthy said, “will give our committees the full power to gather all the facts and answers for the American public.”

Mr. Comer, Kentucky Republican, wrote to Mr. Blinken that the panel wants information about the State Department’s “perception” of the prosecutor general’s office, then headed by Mr. Shokin. The letter details a Nov. 5, 2015, call between Vice President Biden and then-Ukrainian President Petro Poroshenko that “provided no indication” the United States wanted Mr. Shokin removed.

Weeks later, the removal of Mr. Shokin “became a condition of the $1 billion loan guarantee,” Mr. Comer wrote.

House investigators believe Mr. Biden’s son, Hunter Biden, may have played a role in getting his father to shift his views on Mr. Shokin based on testimony from ex-business partner Devon Archer.

Mr. Archer told House lawmakers in July he believes Hunter Biden and two top Burisma executives phoned Mr. Biden from Dubai on Dec. 4, 2015, to discuss “pressure” the company was facing under Mr. Shokin’s criminal probe of the company. 

Mr. Archer, who is facing a prison term for an unrelated securities fraud conviction, told House lawmakers he was told about the call the following day by one of the Burisma executives. 

“I did not hear the phone call, but he called his dad,” he told House lawmakers in closed-door testimony. 

Mr. Archer testified that company President Mykola Zlochevsky and corporate secretary Vadym Pozharsky were pressuring Hunter Biden to help them thwart Mr. Shokin, who was ramping up an investigation into Burisma and had seized some of Mr. Zlochevsky’s assets. 

• Susan Ferrechio can be reached at sferrechio@washingtontimes.com.