Police were investigating the mysterious death of a 20-year-old woman whose decomposed body was found behind a locked door in a New York University apartment complex. The woman, whose name was not immediately released, was believed to be the daughter of a traveling NYU faculty member. Investigators would treat the death as a homicide until the medical examiner's office completed its investigation, police spokesman Paul Browne said. An autopsy done Monday was inconclusive. More studies were needed to determine the cause of the woman's death, medical examiner's office spokeswoman Ellen Borakove said.