Michelle Trachtenberg's cause of death ruled 'undetermined' as family reportedly declines autopsy

One day after Michelle Trachtenberg was found dead in her New York City apartment, her cause of death remains unclear.

Both the manner and cause of death for Trachtenberg are listed as "undetermined," a spokesperson for the New York City Office of Chief Medical Examiner told Yahoo Entertainment on Thursday. The family has reportedly declined an autopsy.

"Under public health law, families may object to autopsy based on religious belief, and provided there is no suspicion of criminality or compelling public health reason to proceed with autopsy, the medical examiner honors the objection," a representative for the medical examiner’s office told the New York Post.

Police told Yahoo on Wednesday that "criminality is not suspected."

Trachtenberg, well known for roles on Buffy the Vampire Slayer and Gossip Girl, was found dead in her apartment on the morning of Feb. 26. ABC News reported the 39-year-old actress recently underwent a liver transplant and may have been experiencing complications, citing unnamed sources. A source close to the situation confirmed to Yahoo Entertainment that Trachtenberg had a liver transplant.

People reported Trachtenberg was "really down emotionally" last year as she dealt with "health issues."

"She told friends she was struggling," an insider claimed. "She was really, really sick and open with those in her circle about how much she was struggling."

A rep for Trachtenberg did not respond to Yahoo's request for comment.

Podcast host Amanda de Cadenet paid tribute to her friend on Instagram.

"I will always remember you as the young vivacious woman I met when I took this photo of you … Seeing your face from the hospital bed when we FaceTimed recently, even though you did not look like you, your sweetness and humor were still alive," she wrote in a now edited post. "I will not share the details of our conversations over the last 6 months. But you knew that death was a high possibility."

That part was later removed and replaced with a new tribute.

"I want to acknowledge your death because I cared about you. I'm grateful we got to connect, especially in the last few months," de Cadenet wrote. "I will always remember you as the young vivacious woman I met when I took this photo of you."

Trachtenberg reportedly enjoyed dinner with friends at Sartiano's in Manhattan a week ago, according to TMZ. The outlet claimed her mother saw her the night before her death around 10 p.m.

Police confirmed to Yahoo the actress was found "unconscious and unresponsive" in her New York City apartment on Feb. 26. Officers responded to a 911 call around 8:00 a.m. She was pronounced dead at the scene.

"It is with great sadness to confirm that Michelle Trachtenberg has passed away," the actress's publicist Gary Mantoosh told Yahoo Entertainment in a statement. "The family requests privacy for their loss. There are no further details at this time."