As the row over workplace sexism at Uber intensifies, a report has emerged of a group of senior employees, including chief executive Travis Kalanick, visiting an escort/karaoke bar in Seoul in 2014.

The visit to the bar, where patrons select women to sing karaoke with, before typically taking them home, resulted in an HR complaint from one of the Uber employees, a female marketing manager.

News of the trip was made public when Gabi Holzwarth, who was dating Kalanick at the time and attended the bar, gave an interview to tech news site The Information.

Holzwarth says she was motivated to speak out by a recent call from Emil Michael, Uber’s senior VP of business, who was also part of the trip. She says he told her he wanted to make sure that if the story came out, she would say they went to karaoke and “had a good time”.

In response to the claim, Michael told the Information: “Given the intense news cycle I thought it was the right thing to do to reach out and let her know that reporters may try to contact her directly. I have known her for a long time, consider her a friend and did not want her to be taken by surprise. Her recollection of this conversation was different from mine and I am very sorry if the purpose of my call was misunderstood.”

Uber told the Information: “This all happened nearly three years ago. It was previously reported to human resources and in early March was referred to Tammy Albarran and Eric Holder,” the attorneys who are leading an internal investigation into the company’s workplace culture.

Holzwarth says that at the event, the marketing manager was visibly unhappy, and left just a few minutes after four male executives picked out women and headed downstairs to sing. Holzwarth and Kalanick left 45 minutes after that.

More than a year later, Holzwarth said she got back in touch with the manager. The manager said that she had spoken with Uber’s HR leader and Kalanick about the issue.