(CNN) President Donald Trump's son-in-law and senior adviser, Jared Kushner, had his White House security clearance restored Wednesday, a person familiar with the matter said, after months of uncertainty stemming in part from his role in the ongoing investigation by special counsel Robert Mueller.

Kushner met with Mueller's investigators a second time in April and answered questions for seven hours, according to his attorney, Abbe Lowell. He had previously sat for an interview last November that was largely focused on former national security adviser Michael Flynn, who soon after pleaded guilty to charges of making false statements to the FBI.

These developments come as the Mueller's investigators appear to be trying to complete parts of their inquiry.

The Kushner team believes he is now finished with all ongoing inquiries, which also include the investigations by congressional committees, according to a person close to Kushner.

A spokesman for Mueller declined to comment.

"A year ago, Jared was one of the first to voluntarily cooperate with any investigation into the 2016 campaign and related topics," Lowell said in a statement.

"Since then, he has continued this complete cooperation, providing a large number of documents and sitting for hours of interviews with congressional committees and providing numerous documents and sitting for two interviews with the Office of Special Counsel. On each occasion, he answered all questions asked and did everything he could to expedite the conclusion of all the investigations."

Kushner was stripped of his interim clearance in February amid an overhaul of procedures governing access to the nation's most sensitive secrets following the resignation of Rob Porter, the President's staff secretary, who had been allowed to remain in his post for months despite allegations of spouse abuse.

The Mueller probe has also hung over Kushner's status in the White House, in part because some of the matters under investigation relate to his role during the campaign and the transition, including contacts with Russians, as well as events that occurred in the early months of the Trump presidency, such as the firing of former FBI Director James Comey

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White House officials have blamed the delay in Kushner receiving his security clearance on administrative backlogs normal to a new administration, as well as the complicated nature of his application. But Kushner's troubles were compounded at least in part because his initial security clearance application didn't list dozens of foreign contacts that he later included in updated submissions to the FBI.

Lowell disputed that the initial security clearance application played any role in the delay in Kushner receiving his final clearance.

"With respect with the news of his clearance being restored, as we stated before, his application was properly submitted, reviewed by numerous career officials and went through the normal process," Lowell said. "Throughout the process, Mr. Kushner has continued to work on a number of foreign policy and domestic issues with no interruption. Having completed all of these processes, he is looking to continue to do the work the President has asked him to do."