Beloved Gossip Girl actress Michelle Trachtenberg, who died unexpectedly at age 39 in February, likely passed from diabetes-related complications, New York City’s medical examiner said Wednesday.

Known for her many roles in popular television series, including classic Buffy the Vampire Slayer, the Jewish actress was found unresponsive in her Manhattan apartment. Following medical checks, it is now believed she passed from complications related to her diabetes.

Trachtenberg’s Orthodox Jewish family had rejected an autopsy citing religious reasons. As there were no suspicions of criminality surrounding her death, their wishes were honored.

Toxicology tests were carried out without an autopsy, the examiners office confirmed to the media.

An unnamed source told NBC News Trachtenberg had received a liver transplant before her death, although the reason for the organ transfer is not public knowledge.

Actress Michelle Trachtenberg poses at the 4th annual Critics’ Choice Television Awards in Beverly Hills, California June 19, 2014. (credit: DANNY MOLOSHOK/REUTERS)

The young actress had reportedly been suffering from ill-health for a year prior to her death, an informed souce told People Magazine.

“She was really, really sick and open with those in her circle about how much she was struggling,” they said. She was “pale, gaunt, very thin, and dealing with health issues.”

Mourning Michelle Trachtenberg

“She laughed the fullest at someone’s joke… she cared deeply about her work, she was fiercely loyal to her friends and brave for those she loved, she was big and bold and distinctly herself,” Blake Lively, a Gossip Girl co-star, said on social media.

Buffy the Vampire Slayer star Sarah Michelle Gellar, said: “Michelle, listen to me … Listen. I love you. I will always love you. The hardest thing in this world, is to live in it. I will be brave. I will live … for you.”