Details surrounding Michelle Trachtenberg‘s death remain unknown.

The Gossip Girl alum’s cause of death has been ruled as “undetermined,” the New York City Medical Examiner’s Office confirmed to E! News Feb. 27. The actress’ family objected to an autopsy, according to People, citing the medical examiner’s office, which led to the ruling.

Trachtenberg was found “unconscious and unresponsive” in her Manhattan apartment on the morning of Feb. 26, according to the New York Police Department. Upon arrival at the scene, authorities determined the actress had passed away. She was 39.

At the time of her death, Trachtenberg was recovering from a liver transplant, per ABC News, citing police sources. The sources told the outlet the former child star’s mom was the one found her unresponsive in the apartment.

“The family requests privacy for their loss,” Trachtenberg’s rep told E! News in a Feb. 26 statement. “There are no further details at this time.”

In the wake of her passing, many of the Trachtenberg’s former colleagues shared their condolences and paid tribute. In a statement to E! News, her Harriet the Spy costar Rosie O’Donnell said, “I loved her very much.”