A Columbia University graduate student who was sentenced to at least 15 years in prison for kidnapping and sexually abusing a Barnard College student has won a reversal of his conviction in a ruling that could sharply curtail New York’s Rape Shield Law.

In a 3-1 ruling, the Appellate Division, First Department, ordered a new trial for Oliver Jovanovic, finding that the trial court had improperly excluded e-mail messages in which the Barnard student evidenced an interest in sadomasochistic sex and acknowledged having a sadomasochistic relationship with another man.