Sean Combs’s defense resumed its cross-examination of a former girlfriend on Thursday, focusing on her relationship with the music mogul as he faced a criminal investigation into his conduct.

The former girlfriend — who is known in court by the pseudonym Jane — was with Mr. Combs at his home in Miami Beach, Fla., when CNN published hotel surveillance footage of him assaulting another former partner, Casandra Ventura, in 2016.

“That was just not the man that you knew, right?” Teny Geragos, a lawyer for Mr. Combs, asked of the video.

“No,” Jane replied.

She acknowledged that after the footage came out, her friends told her to leave him, but she stayed in the relationship. Jane said that, at the time, Mr. Combs had never been physically violent with her.

But one month after the release of the video, Jane and Mr. Combs had a violent brawl that left her with a black eye and welts on her forehead, she testified.

Ms. Geragos started on a line of questioning about how Mr. Combs had tried to enter into a “program” after the hotel assault footage was released, but was rejected. An objection from the government ended the subject. The defense has said Mr. Combs’s violence was often connected to drug use.