President Barack Obama’s choice to be the No. 2 official at the Department of Homeland Security used his appearance before a Senate panel Thursday to adamantly deny allegations that he helped a politically connected company obtain a foreign investor visa.

But the lawmakers who may need the most convincing — the eight Republican members of the Senate Homeland Security Committee — weren’t in the room for the nearly two-hour confirmation hearing.

Sen. Tom Coburn of Oklahoma, the panel’s ranking Republican, said in a written statement that he wouldn’t participate in the hearing until the allegations against Alejandro Mayorkas are resolved.

The nomination hit a snag this week after The Associated Press reported that the department’s inspector general is investigating Mayorkas’ role in helping secure a foreign investor visa for Gulf Coast Funds Management, a company run by former Secretary of State Hillary Rodham Clinton’s brother Tony Rodham. The efforts on behalf of Gulf Coast allegedly occurred after the visa application had been denied and an appeal rejected.

Democrats didn’t shy from asking Mayorkas, currently the director of U.S. Citizenship and Immigration Services, to explain what he knew of the investigation, and he said he only learned about it on Monday night, at the same time as lawmakers. Sen. Claire McCaskill of Missouri had to prod Mayorkas to forcefully deny the allegations.

“You’ve got to do a rebuttal here,” McCaskill said. “I don’t think you can talk around it. Say what you want to say. You aren’t going to get another opportunity like this.”

Mayorkas told the committee that suggestions of impropriety on the visa matter were “unequivocally false” and that he had overseen the program “based on the law and the facts, and nothing else.”

“I have never, ever in my career exercised undue influence to influence the outcome of a case,” he said. “I have never based my decisions on who brings a case but rather on the facts and the law.”

The AP obtained a letter from White House counsel Kathryn Ruemmler to the committee stating that the administration has no concerns about Mayorkas’ suitability for the job. She urged the Senate to swiftly confirm him.

Despite the absence of the panel’s Republicans, and many of its Democrats, chairman Tom Carper, D-Del., expressed confidence in the nominee.

“Nothing in my conversations with Mr. Mayorkas or in my review of his FBI file has convinced me that we should not be holding this hearing today,” Carper said.

It remained unclear when the committee would vote on the nomination.

Maryorkas’ nomination took on new importance earlier this month when DHS Secretary Janet Napolitano announced she would be leaving the department in September to take over as president of the University of California. Should Mayorkas be approved by the Senate, he almost certainly would lead the department until a permanent replacement for Napolitano is named.

With Napolitano’s departure, 15 of the department’s 45 top positions will either be filled with an acting official or they are vacant altogether.

Congressional officials briefed on the Mayorkas investigation, who spoke on the condition of anonymity because they were not authorized to release details of the case publicly, said the visa in question was for a Chinese executive. The Homeland Security Department and its and Citizenship and Immigration Services agency have not commented on the investigation.

In an email to lawmakers Monday, the inspector general’s office said that “at this point in our investigation, we do not have any findings of criminal misconduct.”

Rodham’s company said Tuesday it was not aware of the investigation or of any investor visa application being denied.

According to the inspector general’s email to lawmakers, the FBI’s Washington Field Office was told about the Mayorkas investigation in June after it inquired about Mayorkas as part of the White House background investigation for his nomination.

The investigation does not appear to have any direct ties to Clinton’s tenure as secretary of state. Nonetheless, any hint of scandal or even the most tangential connection to Clinton, who is a possible 2016 Democratic presidential candidate, is likely to become fodder for Republican super PACs, which have sought to discredit her record while she maintains a lower profile with private speeches and work on a new book.

The international investor visa program run by USCIS, known as EB-5, allows foreigners to get visas if they invest $500,000 to $1 million in projects or businesses that create jobs for U.S. citizens. The amount of the investment required depends on the type of project. Investors who are approved for the program can become legal permanent residents after two years and can later be eligible to become citizens.

(AP)