There were concerns about Trump on January 6.
The official said that if Trump went to the Capitol it would be insurrection.
The testimony was played during the hearing.
There were fears that a "coup" could happen if President Donald Trump went to the Capitol on January 6.
The security aide told the committee that they were all in a state of shock. "I think the physical feasibility of doing it, and then also, we knew what that implicated and what that meant, that this was going to move to something else if he physically walked to the Capitol."
The security official's testimony seems to confirm what Cassidy Hutchinson had said. Hutchinson said that Trump didn't care that people were trying to attend his rally with guns.
The first meeting of the House committee looking into the Capitol attack took place on Thursday. The testimonies of William Barr, the former attorney general, and the former president's daughter were included in the hearing.
The security official said that there could be trouble if the president went to the Capitol. Several witnesses testified before the January 6 committee that Trump and his associates planned for days for him to march to the Capitol as lawmakers certified his election loss.
"If you want to use the word insurrection, coup, whatever, we all knew that this would move from a normal, democratic event into something else," the security official said.
According to the January 6 panel members, the security official is unnamed because they fear for the person's safety if they tell the truth.
Trump has denied that he asked his security officials to stop using metal detectors. Hutchinson took the witness stand under oath. He made his claims on social media.
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