Hayden Panettiere died at the age of 36 from an accidental overdose involving the toxic effects of fentanyl and several other substances, according to the Greenville County Coroner’s Office in South Carolina.

The actress, widely recognized for her roles in television series such as Heroes and Nashville, was found unresponsive on August 16 at an apartment in Greenville where she had been staying. Emergency responders performed advanced cardiac life support for over 40 minutes before she was pronounced dead.

An autopsy and toxicology results determined her cause of death was due to the toxic effects of fentanyl, along with 4-ANPP, alprazolam, methocarbamol, and quetiapine. The coroner confirmed there were no signs of trauma and officially ruled the manner of death an accident.

Local authorities and the police department indicated that the investigation into the circumstances remains ongoing, though preliminary findings showed no indications of foul play. Panettiere was open during her life about her personal struggles with substance abuse, postpartum depression, and recovery, which she also detailed in her memoir.