A former associate at Debevoise & Plimpton who used a teenage boy in Moscow as a “sex slave” has been sentenced to 15 years in prison by a Pennsylvania federal judge on charges of traveling for the purpose of engaging in sex with a minor.

Kenneth Schneider was one of the original lawyers working in Debevoise’s Moscow office when it opened in 1998, the firm confirms. That summer, according to U.S. Immigration and Customs Enforcement, which investigated the case, Schneider told two ballet instructors at the Moscow State Academy of Choreography that he was willing to provide “assistance” to students attending the academy.