Carrie Fisher's death certificate was released on Friday, giving only a partial explanation for why the Hollywood icon died last month.
In the official document obtained by ET, the cause of death is listed as "cardiac arrest/deferred," which could indicate that while it has been determined that Fisher suffered a massive heart attack, more tests may be needed to determine the cause of the attack.
WATCH: Todd Fisher Explains Carrie Fisher's Giant Prozac Pill Urn
The Star Wars actress died on Dec. 27 after going into cardiac arrest on a flight from London to Los Angeles on Dec. 22. One day after Fisher passed, her mother, Debbie Reynolds, died of a stroke. ET also obtained Reynolds' death certificate, which confirmed that the Singin' in the Rain star died of an intracerebral hemorrhage and hypertension after suffering from high blood pressure for years.
Both stars were honored in the first-ever Golden Globes In Memoriam tribute on Sunday.
After a brief introduction from host Jimmy Fallon, Reynolds and Fisher were remembered in a video reel highlighting their cinematic accomplishments through the years, set to Reynolds' performance of the song, "You Made Me Love You." The tribute concluded with footage of the duo sweetly embracing on-stage, followed by an on-screen slate of their names and a simple heart graphic.
WATCH: Carrie Fisher and Debbie Reynolds Honored During First-Ever Golden Globes In Memoriam Tribute
Reynolds was laid to rest at Forest Lawn Memorial Park in Los Angeles on Friday along with some of Fisher's ashes. Sources tell ET that a public memorial for both Reynolds and Fisher is being planned for months down the road.