Upon arriving at the luxury apartment building, officers found a 39-year-old woman unconscious and unresponsive; EMS officials responded to the scene and found the actress dead. Gary Mantoosh,

Michelle Trachtenberg was found in her New York City apartment, and the death is not believed to be suspicious, police said.

News of Michelle Trachtenberg's death prompted tributes from her friends and former "Buffy," "Harriet the Spy," and "Gossip Girl" costars.