Mr. Barth said the alleged episode did not involve any current or former members of A.B.T. and was not related to Mr. Gomes’s “employment duties” with the company.

Mr. Gomes did not immediately respond to an email or a voice mail message seeking comment. But Lisa Linden, a spokeswoman for Mr. Gomes, said in an emailed statement: “This is a time of reflection for Marcelo. He is gratified and strengthened by the support he has received from family, friends and colleagues. We have no further comment at this time.”

Neither A.B.T. nor the law firm that was handling the investigation would give further details about the accusation against Mr. Gomes. “A.B.T. does not tolerate the alleged behavior,” Mr. Barth said in his statement. “I am profoundly disheartened by this matter,” he added.

Mr. Gomes, 38, began dancing in his native Brazil. He joined the American Ballet Theater in 1997 and became a principal dancer in 2002. His last performance with the company was in “The Nutcracker” on Dec. 9.

As a performer, Mr. Gomes was known for his strength, stage presence and versatility. He was also a choreographer and the subject of a documentary, “Anatomy of a Male Ballet Dancer,” which is scheduled to premier at Film Forum in New York City next month. The film’s directors did not immediately respond to an email or a voice mail message seeking comment on Thursday.