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."
Describing the loss as "heartbreaking," she continued of Trachtenberg, "She struggled the last few years. I wish I could have helped."
Meanwhile, Trachtenberg's Buffy the Vampire Slayer castmate James Marsters said his "heart is heavy" after learning of her passing.
"We have lost a beautiful soul," he wrote on Instagram Feb. 26. "Michelle was fiercely intelligent, howlingly funny, and a very talented person. She died much too young, and leaves behind scores of people who knew and loved her."
David Boreanaz, who also starred in the supernatural series, added that it was "horrible" to hear news of her death, writing on social media, "So very sad."
In her final years, Trachtenberg lived a quieter life away from the cameras. Her last TV credit was for her reprised role as Georgina Sparks on the 2022 reboot of Gossip Girl.
In January 2024, she addressed online concerns for her health, writing in response to criticism about her appearance, "Explain to me how I look sick."
"Did you lose a calendar and not realize I'm not 14," she added at the time. "How sad for you to leave such a comment."
Read on for a look at Trachtenberg's life in photos.
1996
1996
Harriet the Spy
1998
1999
1999
2001
Buffy the Vampire Slayer
2001
2002
Buffy the Vampire Slayer
2002
2003
2004
2005
Ice Princess
2008
2009
2009
2010
2011
2012
Gossip Girl
2012
2013
2014
2015
2017
2019
2020
2022
Gossip Girl
2023