The 27-year-old singer alleges that David Mueller grabbed her by the buttocks during a photo opportunity at a 2013 concert in Denver.
The 27-year-old singer alleges that David Mueller grabbed her by the buttocks during a photo opportunity at a 2013 concert in Denver -- while he is counter-suing, arguing that the accusations are false and cost him his job.
Andrea Swift, a member of her daughter's senior management group, told the Denver federal court she knew something was wrong as soon as they returned to the "Bad Blood" singer's dressing room.
"When she told me someone had grabbed her, I was very upset," Andrea Swift said, describing her daughter as "really shaken" and humiliated.
"I know what happened. I heard it from my daughter's mouth," Swift told the jury.
"That guy," she added, pointing to Mueller. "He sexually assaulted her."
Since the Denver incident, the singer has changed how she handles meetings with fans, cutting back on meet-and greet opportunities, her mother said, and avoiding going into the audience during gigs.
"It absolutely shattered us, this incident," Andrea Swift said.
Frank Bell, the Grammy Award-winning chart-topper's radio liason, backed up Swift's version of events, what she said to him immediately after the photo session.
Bell told the court Swift had said: "This guy from radio stuck his hand up my skirt and grabbed my bare ass."
Mueller had given evidence in the morning session, conceding that a picture taken during the alleged assault could be interpreted as incriminating.
"Someone could have concluded it appeared she was trying to get away from me," Mueller said.
The photograph of Swift, Mueller and his girlfriend at the pre-show meet-and-greet shows the morning presenter on radio station KYGO with his hand behind the singer. Mueller claims his knuckles may have touched her ribs, well above where his arm is shown.
Swift maintains he sexually assaulted her by lifting her skirt and fondling her buttocks.
Mueller denied the charge, but admitted he did not know where his hand was because he was looking at the photographer.
"If anyone touched her rear, she had a right not to like it. I didn't want to hurt Ms. Swift," Mueller told the court.
The singer, who was 23 at the time, did not file a police report because she did not want the incident made public, her attorney Doug Baldridge said.
Swift's security guards threw Mueller out of the Pepsi Center and told him he was banned for life from Swift concerts.
The star's staff reported the incident to KYGO executives who fired Mueller two days later for violating the morals clause of his contract, the court has heard.
Mueller filed a lawsuit seeking almost $3 million in lost and future wages because of "slander" from members of the Swift camp, while Swift has counter-sued for the alleged sexual assault.
The singer, who was joined in court by her mother and father Scott Swift, has said she will donate any damages awarded in her suit to charities that fight sexual assault on women.