Some House lawmakers are "frustrated" with the changes in the investigation into the attempted assassination of former President Trump, Rep. Lisa McClain told Fox News Digital. 

McClain, who sits on several committees, including Oversight and Accountability and Armed Services, said Homeland Security Secretary Alejandro Mayorkas has taken over the investigation, prompting concerns from lawmakers. 

The U.S. Secret Service, which is investigating the shooting, falls under Homeland Security. 

"They're very frustrated, which is probably a mild understatement," McClain said while at the Republican National Convention in Milwaukee. "There was an assassination attempt on the leading candidate. We're not getting a lot of answers. We're not being transparent. It's being shuffled from the Secret Service to Homeland Security. Why?"

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Homeland Security Secretary Alejandro Mayorkas

Homeland Security Secretary Alejandro Mayorkas speaks at a press briefing. (AP Photo/Jacquelyn Martin)

Another point of concern is Mayorkas being involved in the probe, McClain said, given the opposition against him by many Republicans because of his handling of the southern border. 

"The gentleman that says the border is secure as millions of illegals pour through our borders," she said. "We're not very optimistic. We're not very hopeful."

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Donald Trump gestures with a bloodied face as multiple shots rang out during a campaign rally

Former President Trump gestures with a bloodied face after multiple shots rang out during a campaign rally in Butler, Pennsylvania, July 13, 2024. (Reuters/Brendan McDermid)

The Secret Service has come under heavy scrutiny after the shooter was able to take a shot at Trump from outside the security perimeter. The agency and local authorities have pointed fingers at each other for the security lapse.

"At that particular site, we divided up areas of responsibility, but the Secret Service is totally responsible for the design and implementation and the execution of the site," Secret Service Director Kimberly Cheatle said in an interview with CNN.

McClain said the director needs to take responsibility for what happened. 

Trump being pulled off stage and Secret service director Cheatle

Trump being pulled off the stage and Secret Service Director Kimberly Cheatle. Some House lawmakers are "frustrated" with the probe into the assassination attempt on Trump and Cheatle's response. (Kamil Krzaczynski/AFP via Getty Images | Rebecca Droke/AFP)

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"The Secret Service needs to come out and say ‘Hey, I own this. This is my department. I’m the leader. I'm in charge. I will investigate this,'" McClain said. "We have got to take this seriously, and we've got to get to the bottom of it."