LOS ANGELES (AP) - Officials say actress Carrie Fisher died from sleep apnea and a combination of other factors, but they could not conclusively determine what caused her death.

Los Angeles coroner's officials said in a news release late Friday that Fisher had buildup of fat in the walls of her arteries.

The release states that Fisher had taken multiple drugs prior to her death, but that investigators could not determine whether they contributed to her death in December.

The agency did not immediately respond to a request for additional details about whether a full autopsy report and toxicology results were available.

Fisher suffered a medical emergency on an international flight on Dec. 23. Her mother, longtime movie star, Debbie Reynolds, died the following day.

Actresses Debbie Reynolds (L), recipient of the Screen Actors Guild Life Achievement Award, and Carrie Fisher at the 21st Annual Screen Actors Guild Awards on January 25, 2015 in Los Angeles, California. (Photo by Ethan Miller/Getty Images)