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

Michelle Trachtenberg is dead. She was found lifeless in an apartment by her mother. The actress was only 39 years old and the cause of death is being investigated.

Michelle Trachtenberg's cause of death was ruled "undetermined" by the Office of Chief Medical Examiner in New York City, Fox News Digital confirmed.

Before her death at 39, Michelle Trachtenberg wrote a screenplay titled, 'Toy Monster.' Producer Casey Tebo exclusively tells PEOPLE that studio executives struggled to see the late actress for anything beyond her iconic television roles,

Police told the Post that Trachtenberg was found "unconscious and unresponsive" by police and was pronounced dead by EMS workers. Her death is not being treated as suspicious, police sources told the outlet,

The creators and cast of “Gossip Girl” are paying tribute to actor Michelle Trachtenberg ... Police confirmed Trachtenberg’s death after responding to a 911 call in New York City.

Michelle Trachtenberg, an actress best known for her roles in "Buffy the Vampire Slayer" and "Gossip Girl," has died at age 39.

Michelle Trachtenberg had written an 'incredible' screenplay based on Jerry Oppenheim's 'Toy Monster,' according to producer Casey Tebo, but he says studios overlooked the star's talent for writing.

Michelle Trachtenberg was embarking on a new path as a screenwriter before her death at the age of 39. The actress was on the verge of closing a deal on a screenplay she'd written based on the book Toy Monster: The Big,

New York City native and "Gossip Girl" and "Buffy the Vampire Slayer" actress Michelle Trachtenberg has died at 39.