Michelle Trachtenberg Said Rosie O'Donnell 'Protected Me So Much' on Set ofHarriet the Spy

News ofMichelle Trachtenberg’s tragic deathon Feb. 26 at the age of 39 is bound to hit fans ofHarriet the Spyparticularly hard. The actress was just 10 years old when she made her film debut in the 1996 movie based on the beloved 1964 children’s novel, starring as the titular Harriet oppositeRosie O’Donnellas nanny and confidant “Ole Golly.” Trachtenberg went on to play memorable roles inBuffy the Vampire SlayerandGossip Girl, butHarrietalways held a special place in her heart.

Michelle Trachtenberg Wrote a Screenplay Before Her Death but Producer Says Studio Couldn't Recognize Her 'Incredible' Writing

Michelle Trachtenberg.Photo:Jemal Countess/Getty Jemal Countess/Getty Michelle Trachtenbergwas not only a gifted performer, but also an accomplished writer. Before hersudden death at 39, theGossip Girlalum was working on a screenplay for a film titledToy Monster, based on Jerry Oppenheimer’s book of the same name. Casey Tebo, who was attached to the project as a producer, exclusively tells PEOPLE how passionate she was about the screenplay and how her talents as a writer blew him away.

Michelle Trachtenberg's Cause of Death Is Ruled 'Undetermined' After She Dies Suddenly at 39

Answers aroundMichelle Trachtenberg’s cause of death may continue to linger. According to the New York City Medical Examiner’s Office, the actress' family objected to an autopsy, leaving her cause of death to be ruled “undetermined,” PEOPLE confirms. Due to the family’s request, the medical examiner was only allowed to conduct an external exam of Trachtenberg’s body. Trachtenberg was 39 when she was found dead in an apartment on Feb. 26. The NYPD previously confirmed to PEOPLE that police responded to a 911 call at 1 Columbus Place around 8 a.

Michelle Trachtenberg's Ex Zane Carney Shares Tribute to His 'First Love,' Says They 'Stayed in Touch All These Years'

Zane Carney; Michelle Trachtenberg.Photo:Amanda Edwards/Getty; Jamie McCarthy/Getty Amanda Edwards/Getty; Jamie McCarthy/Getty Michelle Trachtenberg’s ex Zane Carney is mourning the loss of his “first love” following news ofher sudden deathat 39. The NYPD told PEOPLE that officers responded to a 911 call on Wednesday, Feb. 26, pronouncing the late actress as deceased. In a heartfelt tribute shared toInstagramon Wednesday, Feb. 26, the guitarist, also 39, recalled how he met and fell in love with the late actress when the two were just kids.

Michelle Trachtenberg's Family: All About the Late Actress' Parents and Sister — and Why Her Mom Was Her 'Inspiring Force'

Michelle Trachtenberg and mom Lana. ; Michelle Trachtenberg and sister Irene.Photo:J. Vespa/WireImage (2) J. Vespa/WireImage (2) Michelle Trachtenbergcounted her parents and sister as her biggest supporters before her death at age 39. The actress, whodied on Feb. 26, got her start as a Nickelodeon child star in the 1990s before rising to fame with roles inBuffy the Vampire SlayerandGossip Girl. In a March 2005 interview withBlackfilm, Michelle shared that although her mom, Lana, was “never a stage mom,” she had “always been there.