The cause of death for Michelle Trachtenberg, the “Gossip Girl” and “Buffy the Vampire Slayer” star, will remain undetermined as her family declined an autopsy, Variety has confirmed.

Michelle Trachtenberg was close to closing a deal for a screenplay she had been working on for years before her shocking death last week, TMZ reports. Speaking to a director and producer involved with the project,

The death of Michelle Trachtenberg one week ago was definitely a shock, and tributes to the late actress have ben rolling in from the Buffy cast and more. While her passing was a surprise, Trachtenberg’s friends recently opened up about the health issues she'd be not-so-privately dealing with.

Michelle Trachtenberg was in poor health before she died at age 39 on Feb. 26. Several sources spoke to Us Weekly about the “Gossip Girl” alum’s final days after she got a liver transplant, which may have contributed to her death.

Michelle Trachtenberg was found unconscious and unresponsive at her midtown NYC apartment by her mom, Lana. She was just 39 years old. "It is with great sadness to confirm that Michelle Trachtenberg has passed away,