(Jenny Starrs/The Washington Post)

Rep. Jason Chaffetz, chairman of the House Oversight and Government Reform Committee, said Thursday that he will leave Congress on June 30, citing “big changes in his life” in a public letter to constituents.

“Julie and I are facing the reality of being empty nesters,” he wrote. “All of us, it appears, are ready to begin a new chapter.”

Chaffetz’s departure opens up one of the most powerful and closely scrutinized posts on Capitol Hill — the House majority’s chief inquisitor — amid serious questions about wrongdoing at the highest levels of the Trump administration.

An early favorite for the post emerged Thursday: Rep. Trey Gowdy (R-S.C.), who led the contentious House investigation into the 2012 terrorist attacks on a U.S. outpost in Benghazi, Libya — though it was unclear whether Gowdy would accept the job.

Chaffetz (R-Utah) announced last month that he had “made a personal decision to return to the private sector” and would not seek reelection or run for any other political office in 2018. He has not ruled out a run for Utah governor in 2020.

Rep. Jason Chaffetz (R-Utah) had earlier said he would not seek reelection or run for any other political office in 2018. (Kim Raff for The Washington post)

The decision comes days after Chaffetz took an aggressive posture after reports emerged that former FBI director James B. Comey alleged in private memos that he had been pressured by President Trump to end an investigation into Michael Flynn, Trump’s national security adviser at the time.

Chaffetz requested those memos and other records from the FBI on Tuesday. On Wednesday, he scheduled a hearing for next week in anticipation that Comey might testify.

But the probe is certain to continue under a new chairman. The internal jockeying among House Republicans to succeed Chaffetz in that high-profile role kicked off Thursday, with at least three Oversight Committee members phoning members of the House Republican Steering Committee, which will select his successor.

Multiple Steering Committee members said they had been contacted by Gowdy, Dennis A. Ross (Fla.) and Steve Russell (R-Okla.) about their interest in the post.

It is Gowdy, several leading House Republicans said Thursday, who has a clear leg up in the contest. He is a former state and federal prosecutor who led the high-profile, two-year Benghazi investigation, and he is well liked inside the House GOP.

“If he wants it, it’s his, no question,” said one Steering Committee member who spoke on the condition of anonymity to comment frankly about the pending race.

“I think he would have a pretty good shot at it,” said Rep. Douglas A. Collins (R-Ga.), the vice chairman of the House Republican Conference.

Gowdy did not answer questions Thursday about his interest in the position, and his spokeswoman acknowledged discussions but would not say he is actively seeking the post.

“Representative Gowdy is talking to members in the conference about the qualities they believe are most important for the next chairman to possess,” said the spokeswoman, Amanda Gonzalez.

There are complications should Gowdy choose to seek the Oversight Committee chairmanship: Another member of the panel, Rep. Jim Jordan (R-Ohio), has more seniority than Gowdy and strong support among the handful of hard-line conservatives who serve on the panel.

But his role as a founder of the hard-right House Freedom Caucus has made him less appealing to the mainstream conservatives who make up the bulk of the Steering Committee.

Jordan previously fell short in a 2014 bid for the Oversight Committee gavel. A spokesman, Darin Miller, said Jordan had not decided whether to seek it again.

Rep. Mark Meadows (R-N.C.), the chairman of the Freedom Caucus, acknowledged a “huge push” for Gowdy in some GOP circles Thursday but said choosing him would be a “punch in the nose” to Jordan.

“My personal feeling is that Trey Gowdy will not take a chairmanship gavel, because of his friendship and respect for Jim Jordan, who is ahead of him in both seniority and based on merits,” he said. “If Jordan gets jumped over at this point, we can say that it’s not based on merit. The question that must be asked is, what’s it based on?”

Ross said Thursday that he was interested in the post only if Gowdy decides not to accept it.

“I’d like to see Trey do it,” he said. “I think he’d be very good at it, but if he doesn’t, I’ll consider it then.”

Gabriel M. Bastomski, a spokesman for Russell, confirmed Russell was seeking the chairmanship regardless of Gowdy’s intentions. “He has spoken to Mr. Gowdy about running and was encouraged by Mr. Gowdy to stay in the race,” he said.

As the head of the House’s main investigative committee since 2015, Chaffetz became a prime critic of President Barack Obama’s administration and, crucially, former secretary of state and presidential nominee Hillary Clinton. But until his decisive moves this week, critics suggested that he had been less interested in probing potential wrongdoing inside the Trump administration.

Utah House Speaker Greg Hughes told the Salt Lake Tribune on Wednesday that Chaffetz was expected to resign within a few days. Politico first reported news of an impending announcement Thursday.

David Weigel contributed to this report.