An investigation into accusations of sexual misconduct against opera singer Plácido Domingo by opera performers’ union found that he “engaged in inappropriate activity, ranging from flirtation to sexual advances, in and outside of the workplace” when he was a senior executive at the Washington National Opera and Los Angeles Opera, according to the Associated Press and the New York Times.

The results of the investigation by the  the American Guild of Musical Artists, which involved more than 20 women and were released Tuesday, elicited another apology from the 79-year-old singer, who has lost bookings and posts due to the accusations, which first surfaced last year.

“I have taken time over the last several months to reflect on the allegations that various colleagues of mine have made against me,” he said in a statement. “I respect that these women finally felt comfortable enough to speak out, and I want them to know that I am truly sorry for the hurt that I caused them.”

“I accept full responsibility for my actions, and I have grown from this experience,” he continued. “I understand now that some women may have feared expressing themselves honestly because of a concern that their careers would be adversely affected if they did so. While that was never my intention, no one should ever be made to feel that way.”

While several American companies, including the Metropolitan Opera and the San Francisco Opera, canceled Domingo performances after the allegations arose, several European ones said they would make a decision after the investigation was completed.

The investigation, conducted by lawyers hired by the American Guild of Musical Artists, concluded that the accounts from 27 people showed a “clear pattern of sexual misconduct and abuse of power by Domingo spanning at least two decades,” according to The Associated Press. Lawyers from the firm Cozen O’Connor interviewed 55 people last fall, according to the AP, of which 27 said they experienced or witnessed sexually suggestive behavior by Domingo over the years.

Domingo initially disputed the accusations when they first arose last August, when the AP reported that nine women — one named, seven anonymous — had described being harassed by Domingo, with charges ranging from kissing and groping to threatening careers. In response, Domingo attributed some of the firestorm to changing mores: “I recognize that the rules and standards by which we are — and should be — measured against today are very different than they were in the past.” But he also said he believed any interactions with these or other women were “welcomed and consensual.”

A second AP story included even more allegations of groping, leading spokesperson Nancy Seltzer to accuse the AP of painting “a misleading picture… riddled with inconsistencies and, as with the first story, in many ways, simply incorrect.”