WASHINGTON – Members of Congress will have their first – and probably only – chance to question acting Attorney General Matthew Whitaker on Friday, and there’s a lot they want to ask: Has the White House tried to interfere in the criminal investigations surrounding the president? Has Whitaker revealed secrets to the White House?

And the question that has confounded Washington for months: Is the investigation of Russian election interference that has shadowed the first two years of President Donald Trump’s administration really about to end?

Whitaker's desire to answer those questions appeared in question on Thursday, as he fought with lawmakers over whether they could force him to talk about his conversations with the president. The Justice Department said late Thursday that Whitaker would testify before the House Judiciary Committee on Friday.

The hearing is scheduled for 9:30 a.m. EST.

Earlier in the day, the committee authorized its chairman, Rep. Jerrold Nadler, D-N.Y. to serve a subpoena on Whitaker if he declined to answer lawmakers' questions. The Justice Department replied that he would appear only if the subpoena threat was withdrawn. The department said in a statement that Whitaker changed his mind and agreed to testify after Nadler assured him that there would be no subpoena if Whitaker appeared before Congress and answered lawmakers' questions.

Whitaker has presided over special counsel Robert Mueller’s investigation since Trump ousted Jeff Sessions as attorney general in November. Whitaker said last month that the investigation was “close to being completed,” the first time anyone familiar with its inner workings had offered even a hint in public of its likely trajectory. He did not elaborate.

Democrats on the panel said they’re eager to know what he meant. “By saying this is close to being wrapped up, are those his wishes or the words of the Mueller team? I think those are fair questions,” said Rep. Eric Swalwell, D-Calif. He said lawmakers deserve an assurance that the special counsel “still has the freedom of movement that it needs to pursue leads.”

If Mueller’s work is nearing its end, it’s giving outward signs of an investigation still gathering evidence.

Lawyers for the special counsel are fighting two cases in which witnesses have defied orders to testify before Mueller’s grand jury. One, involving an unnamed company owned by a foreign government, awaits review in the Supreme Court.

The lawyers confirmed in a court filing that Rick Gates, Trump’s former deputy campaign chairman who pleaded guilty to charges of conspiracy and lying to investigators, “continues to cooperate with respect to several ongoing investigations.” Prosecutors and Gates’ lawyers said it will be at least mid-March before they’re ready to set a date for him to be sentenced.

Two weeks ago, FBI agents gathered troves of electronics and other materials from the home, apartment and office of longtime Trump confidant Roger Stone, whom they charged with lying to Congress. Prosecutors said they seized so much information that they might not be ready to bring him to trial until October.

“From what we can see, I’m skeptical that he’s close to wrapping up,” said Randall Eliason, a George Washington University law professor and former federal prosecutor.

Lawmakers said they plan to press Whitaker to explain what he meant.

“It was inappropriate for him to talk about a timeline for the ending of a criminal investigation,” said Rep. Ted Lieu, D-Calif. “The reason that prosecutors don’t talk about timelines is with every new witness or new tranche of evidence you uncover, it could lead to additional witnesses, additional leads.”

Whitaker has been a polarizing figure since he took over the Justice Department. Some Democrats and Republicans in Congress questioned the legality of his appointment, arguing that he needed to be confirmed by the Senate.

Not long after he took the job, Whitaker said he disregarded advice from the department’s career ethics lawyers that he disqualify himself from overseeing the Russia investigation because of comments he’d made questioning the inquiry and suggesting that the department could starve it of funding to bring it to an end. Lawmakers said they plan to press him on that, too.

In a letter to lawmakers Thursday, the Justice Department said the White House had not asked Whitaker to make any promises about Mueller's investigation, and he had not made any. Assistant Attorney General Stephen Boyd wrote that under Whitaker's watch, the department has made its decisions "based upon the facts and law of each individual case" and "independent of any outside interference."

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Whitaker has presided over a period in which tandem criminal investigations around the president have intensified. Under his watch, Mueller’s office arrested Stone, Trump’s longtime adviser, on charges of lying to Congress about his efforts to learn about emails the Russian government hacked during the 2016 campaign. A separate team of prosecutors said in a court filing that Trump’s former personal lawyer, Michael Cohen, made illegal hush-money payments to two women “at the direction of” Trump.

Prosecutors in that case identified Trump with the pseudonym “Individual-1.” Nadler said in a letter to Whitaker that among the questions he wants answered is how the president reacted to the accusation.