Medical examiners in South Carolina have ruled the death of 36-year-old actress Hayden Panettiere an accidental overdose. An autopsy by the Greenville County Coroner's Office found no physical trauma and instead identified toxic levels of multiple substances in her system.

Drug tests revealed fentanyl, Xanax, methocarbamol, and quetiapine. Methocarbamol is a prescription muscle relaxant. Quetiapine is an antipsychotic medication used to treat certain mental health conditions. Fentanyl is a synthetic opioid that has caused hundreds of thousands of American deaths over the past five years.

Panettiere died last month after she was found unresponsive at a South Carolina residence. She starred in the US television series Heroes and Nashville. She had previously spoken openly about her struggles with substance abuse.