Former Trump campaign manager Corey Lewandowski huddled with Senate Intelligence Committee investigators for more than three hours Wednesday, according to a person familiar with the matter.

Lewandowski is one of several Trump campaign officials whom the Senate Intelligence Committee has interviewed in recent months as part of its probe into Russian meddling in the 2016 U.S. presidential elections and allegations that the Trump campaign colluded with Russian officials.

Committee staffers have also interviewed Trump's senior adviser and son-in-law, Jared Kushner, and Paul Manafort, who succeeded Lewandowski as Trump's campaign manager. Trump fired the combative Lewandowski in June 2016 after turf battles with other members of the then-candidate's inner circle.

As campaign manager, Lewandowski was looped in on a Trump campaign staffer's efforts to broker a meeting between Trump and Russian President Vladi­mir Putin, though it is unclear whether Lewandowski played a role in the planning.

Even after his official departure, Lewandowski maintained close ties with the campaign and was on the campaign payroll as recently August of last year.

Lewandowski's interview with Senate investigators occurred on the same day that the House Intelligence Committee attempted to obtain depositions from senior executives of Fusion GPS, the firm behind a salacious dossier detailing allegations stemming from Trump's personal and business dealings in Russia, as part of their probe into allegations of Russian meddling.

House Intelligence Committee Chairman Devin Nunes (R-Calif.) approved subpoenas for senior executives of Fusion GPS this month. Senior executives Thomas Catan and Peter Fritsch spoke behind closed doors Wednesday morning but refused to answer questions, invoking the First Amendment and their Fifth Amendment rights against self-incrimination.

"No American should be required to appear before Congress simply to invoke his constitutional privileges," said Josh Levy, a lawyer for the executives, calling the proceedings an "indignity" that even Watergate investigators didn't foist upon their witnesses.

"Our clients have cooperated with Congress. We have worked with the other committees investigating this matter to strike the balance between Congress's right to information and our client's privileges and legal obligations," Levy said in an emailed statement, referring to an August meeting Senate Judiciary Committee investigators held with Fusion GPS's chief executive, Glenn Simpson.

Simpson did not meet with the House Intelligence Committee on Wednesday, which conducted the depositions with Catan and Fritsch as two separate, 45-minute meetings. Rep. Thomas J. Rooney (R-Fla.), who is one of two members assisting Rep. K. Michael Conaway (R-Tex.) with running the investigation, was the only member of the committee to be identified as present during the interviews alongside staff members.