A student at the University of Central Florida shared videos of sexual encounters he had with his girlfriend in a secret Facebook group for his fraternity brothers without her permission, the woman alleges in a lawsuit filed on Thursday.

Kathryn Novak, a student in Arizona, said she learned in March that her intimate photos and videos had been shared in a secret Facebook group when she saw someone’s text message to her long-distance boyfriend that mentioned a sexual video. Her boyfriend, Brandon Simpson, did not deny sharing the video in the Facebook group named “Dog Pound” in October, according to the lawsuit.

Ms. Novak’s lawyer, Michael Avenatti — who is best known for representing Stephanie Clifford, the porn actress professionally known as Stormy Daniels, in her lawsuit against President Trump — said in an interview on Thursday that the sharing of Ms. Novak’s images had been “devastating to her.”

“The fact that you had a basically frat-boy atmosphere, both literally and figuratively, that was centered on the exploitation of women without their knowledge or consent is outrageous,” he said.