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Former deputy national security adviser K.T. McFarland said on Thursday that Joe Biden’s son controversial involvement with a Ukrainian gas company while his father served as vice president should be further scrutinized ahead of the election.

“I always wondered about why the Senate never called Hunter Biden to talk about the contracts he had with Ukraine as part of the impeachment or even with his contracts with China,” McFarland told “America’s Newsroom.”

She said that it's best for the presumptive Democratic presidential nominee to have the details investigated now, as Democrats in the Senate could ask their own questions in an open hearing.

"It's gonna come out anyway," she argued.

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McFarland's comments came after the Senate Homeland Security and Governmental Affairs Committee on Wednesday voted to subpoena Blue Star Strategies – a company connected to the Ukrainian natural gas firm Burisma Holdings – as part of the panel’s investigation into Hunter Biden’s role on the board of the firm.

The committee voted along party lines, 8-6, to subpoena Blue Star Strategies. Sen. Mitt Romney, R-Utah, who sits on the committee, voted with Republican colleagues to approve the subpoena.

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Committee Chairman Ron Johnson, R-Wis., announced earlier this year his plans to subpoena Blue Star Strategies for records to review potential conflicts of interest in Biden's role on the board of Burisma, and whether individuals at the firm improperly used the relationship with the former Vice President's son to “influence” U.S. government agencies.

The subpoena would cover records dating back to Jan. 1, 2013, regarding their work for Burisma Holdings, or individuals associated with Burisma’s founder, Mykola Zlochevsky. He also wants Blue Star CEO Karen Tramontano and Chief Operating Officer Sally Painter for depositions.

But the head of Blue Star Strategies penned a letter to Johnson and Republicans on the committee on Wednesday morning, highlighting their past cooperation with the panel's requests and questioning why they would subpoena further documents.

McFarland said that congressional members would always make the argument that they did not want to put Hunter Biden in a position that may cause him to “relapse” or have “difficulty" due to his history with substance abuse.

“But, I asked someone close to the whole thing and they said, ‘Well, here’s the thing: everyone likes Joe Biden, he’s a nice guy, and his son Hunter had struggled with substance abuse and was a fragile, frail guy.'”

“My response to that was, 'Why is he taking the money?' It does not pass the smell test. As you just pointed out, even the State Department officials were saying it does not pass the smell test,” McFarland said.

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“Again, bring it out in the open. Sunlight is always the best disinfectant. Let’s see what happened, why did it happen, and the American people can decide in November.”

Fox News' Brooke Singman contributed to this report.