The victim in a violent South End assault on Monday has been identified by friends as Sheldon Lee, the longtime music director at Blessed Mother Teresa parish in Dorchester.

Lee, 65, is a gifted musician and vocalist who as a young man traveled to Italy to train in opera with Luciano Pavarotti. He was attacked in his apartment complex on West Brookline Street. His alleged assailant is a 41 year-old David Eng, who lives in an adjacent apartment, according to the Boston Police.

“For many years, he was the music director at St. William’s,” said Rev. Jack Ahern, pastor of Mother Theresa parish. “He’s the head of the choir, does all the music arrangements at Masses and funerals. He’s a gifted musician.”

Lee was a music teacher in Sudbury before his retirement. He also performs with the Boston Opera Company and the Handel Hayden Society. After eight hours surgery on Monday, he is listed in critical but stable condition, and was scheduled for more surgery on Tuesday, according to Rev. Ahern.

Eng was ordered held on $100,000 cash bail at his arraignment on Tuesday. He is due back in court to face assault with intent to murder charge on Sept. 4.