Avraham Slep, composer, teacher, conductor, and arranger, was born in 1884. It is not known where he was born or where he received his musical education. Slep began his career as a singing teacher at the Vilna Jewish School. There he conducted a choir that brought him professional fame. In the mid-20s, Slep became a professor of solfege at the Vilna Institute of Jewish Music, among whose teachers was Eliyahu Malkin, the teacher of Yasha Heifetz. In the late 1920s, Slep led the Vilner Buildings Gesellschaft (Vilna Educational Society Choir), which soon became the musical symbol of the 'Lithuanian Jerusalem'. Slep also took part in the publication of collections of Jewish songs. So, he edited two collections of songs by Chaim Ritterband published in Vilna: Yiddish Melodien (Jewish Melodies) (1935) and 20 leader mit notes (20 songs with notes) (1938)
During the years of Nazi occupation, Slep was in the Vilna ghetto. He and Tamara Girshovich, a piano teacher, managed to organize a Jewish music school. Whenever possible, Slep and his choir performed in concerts in the ghetto. A few months before the destruction of the Vilna ghetto, Avraham Slep fell ill and was taken to the territory of Estonia, where he was killed during one of the 'actions'. His wife was killed in Majdanek and his son went missing.
Source: 'Avram Sliep' at Yiddish Music Website (in Russian).