Hayden Panettiere, known for her role in the television series Heroes, passed away on August 16 in Greenville, South Carolina. The Greenville County Coroner’s Office confirmed that her death resulted from the toxic effects of fentanyl and four additional substances. These substances included 4-ANPP, a chemical that can be a precursor used in illicit fentanyl production and can also occur as a metabolite of fentanyl. Also found in her system were Alprazolam, Methocarbamol, and Quetiapine, all prescription medications.
Emergency responders arrived at the Greenville apartment where she was found unresponsive after a 911 call reported a cardiac arrest. Panettiere had been temporarily staying at the residence, according to CNN. Her on-again, off-again boyfriend Brian Hickerson and his brother Zach were at the apartment when emergency crews arrived.
Despite efforts including advanced cardiac life support measures, Panettiere was unresponsive and could not be revived. She was pronounced dead at 2:32 p.m. Paramedics had attempted to resuscitate her for more than 40 minutes, according to the Associated Press.
Police confirmed that there were no signs of foul play in the case. The autopsy also found no signs of trauma that contributed to her death. The investigation into the circumstances surrounding her death continues even though the coroner has now determined the cause and manner of death.
Panettiere’s representative urged the public to wait for official findings rather than speculate about what happened.
In the days following her death, her former co-stars and friends gathered for a memorial service in Malibu, California. Connie Britton, who starred with Panettiere in Nashville, was among those who attended. Ruby Rose, Charles Esten, Paris Hilton and Evan Ross were also reported to have attended the September 19 memorial.
Brian Hickerson reportedly gave Panettiere Narcan after finding her unconscious in the apartment. Hickerson and his brother also performed CPR before paramedics arrived, according to TMZ.
Hickerson’s attorney, Sloan Ellis, commented on the case and emphasized that the investigation must proceed without interference. Ellis said there were no signs of foul play and that Hickerson would not make further comments while the investigation remained underway.
The official cause of death was confirmed on September 22, more than a month after Panettiere’s passing. The coroner listed the cause as the toxic effects of fentanyl, 4-ANPP, alprazolam, methocarbamol and quetiapine. Her manner of death was ruled accidental.
Authorities have not publicly established how Panettiere obtained the fentanyl. Federal investigators have reportedly been looking into whether she obtained nonprescription pills from a dealer in the Los Angeles area. The Los Angeles Times reported that the federal investigation has focused partly on identifying the source of the drugs.
Panettiere had publicly discussed her struggles with substance abuse before her death. She also wrote about addiction and other personal struggles in her 2026 memoir This Is Me: A Reckoning.
Panettiere was 36. She was best known for playing Claire Bennet on Heroes and Juliette Barnes on Nashville. Her film credits included Remember the Titans, Scream 4 and Scream VI.