CHICAGO (CBS) — A north suburban man recorded himself laughing as he stormed the U.S. Capitol on Jan. 6, and authorities now say it was a family affair.

Christian Kulas of Lake Forest is expected to plead guilty next month to charges stemming from the insurrection. Authorities also now say his brother, Mark, has been charged.

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Video from an Instagram account provided to federal authorities by a cooperating witness first shows a rally at which President Donald Trump was speaking, then people walking up the steps of the U.S. Capitol and shouting, “Block the steal!”

The video shows a man identified by authorities as Kulas laughing, wearing a dark baseball-type cap with the words “Keep America Great” in bright orange letters, and a dark Burberry coat.

Capitol Riot Image From Kulas Complaint

(Credit: U.S. Attorney’s Office)

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Another video clip from the Instagram account shows the inside of the Capitol, and a man is heard saying, “Storming the Capitol.”

Capitol Riot Image From Kulas Complaint

(Credit: U.S. Attorney’s Office)

Both brothers are scheduled to plead guilty and be sentenced on the same day.

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Mark Kulas is the 14th Illinois resident charged with taking part in the Jan. 6 insurrection.

CBS 2 Chicago Staff