Spanish tenor Placido Domingo speaks to reporters in October ahead of a concert in Moscow.
CNN  — 

An investigator looking into allegations of sexual misconduct against opera star Plácido Domingo has found that the Spanish tenor did make inappropriate sexual advances in the workplace, a US musicians’ union said Tuesday.

Domingo, meanwhile, has released a statement apologizing “for the hurt that I caused” the women who accused him.

The American Guild of Musical Artists’ announcement is the latest development over allegations that were first publicized in August – accusations that led Domingo to resign in October as director of Southern California’s LA Opera and led him to cancel performances in other US venues.

After the accusations became public, the guild hired an investigator, who “concluded that Mr. Domingo had, in fact, engaged in inappropriate activity, ranging from flirtation to sexual advances, in and outside of the workplace,” the guild said Tuesday.

“Many of the witnesses expressed fear of retaliation in the industry as their reason for not coming forward sooner,” the guild said.

Two of Domingo’s accusers and Debra Katz, an attorney for them, on Tuesday called for the union to oust the singer from its ranks, saying the investigation “has exposed overwhelming evidence” of Domingo’s “decades-long predatory behavior.”

“Even though the industry failed to protect us from misogynist and predatory behavior, an expulsion from the union would signal that the industry is learning from its mistakes and that sexual harassment and abuse – perpetuated by industry complicity – will not be tolerated in the future,” Patricia Wulf and Angela Turner Wilson, two of the accusers, said in a statement.

The Associated Press made the first report in August, with nine women alleging that incidents of sexual harassment took place over three decades beginning in the late 1980s. The AP reported the following month that 11 more people came forward with allegations that included verbal harassment and groping. CNN was unable to verify the accusers’ accounts.

Domingo apologizes

Domingo, 79, initially disputed the allegations.

But Domingo on Tuesday released an apology shortly before the guild announced its findings.

“I have taken time over the last several months to reflect on the allegations that various colleagues of mine have made against me,” Domingo’s statement reads. “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. 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. I am committed to affecting positive change in the opera industry so that no one else has to have that same experience. It is my fervent wish that the result will be a safer place to work for all in the opera industry, and I hope that my example moving forward will encourage others to follow.”

Guild calls on performance companies to ‘change the culture’

The guild’s executive director said Tuesday he is calling on opera, dance and choral concert companies to join the union in an initiative to “positively change the culture.”

“This will ensure that artists feel respected and empowered to address sexual harassment and related issues going forward,” guild Executive Director Leonard Egert said.

Details about the initiative will be released in the coming weeks, the guild said.

Domingo is regarded as one of the greatest opera singers of all time. He’s won 14 Grammy and Latin Grammy awards and performed with fellow tenors Luciano Pavarotti and José Carreras as part of the Three Tenors.

The allegations led Domingo in September to cut ties with The Metropolitan Opera in New York, ending a professional relationship that began in 1968. He had been set to perform multiple performances in “Macbeth” and “Madama Butterfly” there. The Dallas Opera also canceled a Domingo performance scheduled for March.

He has performed in Europe since the allegations were reported in August, and he has more European performances scheduled this year.

Domingo resigned in October as director of the LA Opera, which he helped found in the mid-1980s and where he had performed more than 300 times in 31 roles.

The LA Opera said Tuesday its own investigation is still underway.

“LA Opera is in the process of receiving and considering the findings of the independent Gibson Dunn investigation,” a spokesperson for the opera said. “We expect to complete that process shortly and will have further comment at that time.”

CNN’s Kevin Flower, Marianne Garvey and Stephanie Elam contributed to this report.