Helena Duke, 18, received a video clip from a cousin that spread on social media, showing a woman in the middle of a crowd of supporters of President Trump in Washington.
In the video, another woman swings her hands at her face. The first woman hits her back, and then the crowd confronts her.
Duke, a high school senior, recognized the woman who swung her hands as her mother along with her uncle and aunt, The New York Times reported.
Duke and her mother have drifted apart in recent years over their diverging political views. She called her mother out on Twitter, saying "hi my mom remember the time you told me I shouldn't go to BLM [Black Lives Matter] protests because they could get violent...this you?"
She also retweeted the video clip, according to The Times. The tweets were not publicly visible Wednesday.
In a subsequent tweet, Duke called out her relatives by name and said: "This is the liberal lesbian of the family who has been kicked out multiple times for her views."
Duke said she wasn't aware her mother -- a longtime Democrat who threw her support to Trump -- was in Washington.
"I remember seeing the FBI tweets saying that anyone who knows anything about the people that were at the Capitol or anything like to put their names out there," she told the newspaper. "After a lot of thought, I was like, this is really the right thing to do."