Panettiere openly discussed her struggles navigating child stardom and abuse in the entertainment industry

The investigation into the shocking death of Hayden Panettiere has been joined by the Drug Enforcement Administration, a source familiar with the matter told The New York Times.

ABC, which also confirmed the news, stated that the Greenville City Police Department in South Carolina remains the lead investigative agency, and the DEA is assisting.

Greenville police “accompanied by EMS personnel, responded to a report of an unresponsive female” on Sunday (Aug. 16), according to a statement given to NBC News. “Upon arrival, medical assistance was administered; however, the individual, later identified as Hayden Panettiere, was pronounced deceased at the scene.”

On a dispatch audio obtained by People, officials on the call discussed an “overdose” and “cardiac arrest” around the time of Panettiere’s death.

An autopsy was “completed” Monday (Aug. 17), and “no signs of trauma were discovered that would have contributed to the death,” coroner Mike Ellis said in a statement to People earlier this week. “The cause and manner of death remain pending further investigation and the completion of additional studies. This investigation remains active and ongoing. No further details are available for release at this time.”

Panettiere had long been candid about her struggles navigating child stardom and the rampant sexual harassment and abuse in the entertainment industry. In her memoir, This Is Me: A Reckoning, Panettiere also discussed postpartum depression, addiction, and domestic abuse. In the book, the star detailed her prolific and sometimes difficult career in show business; growing up under the harsh light of Hollywood; and the highs and lows of filming hit TV shows like Heroes and Nashville, and more.