More than a month after Hayden Panettiere was found unresponsive inside a South Carolina residence, officials have revealed what caused the 36-year-old actress’s sudden death.

The Greenville County Coroner’s Office announced on September 22 that Panettiere died from the toxic effects of fentanyl combined with several other substances: 4-ANPP, alprazolam, methocarbamol and quetiapine.

Her manner of death has been ruled an accident.

The findings provide the first definitive medical explanation for a case that had generated weeks of questions, conflicting reports and an expanding investigation stretching from South Carolina to California.

Panettiere, known for roles in Heroes, Nashville, Remember the Titans and Scream, died on August 16 while temporarily staying at a residence in Greenville.

She was 36.

Toxicology Provides the Answer Investigators Were Waiting For

Officials had been waiting for toxicology results before making a final determination about Panettiere’s death.

An autopsy conducted shortly after she died found no traumatic injuries that contributed to her death.

That left toxicology as one of the most important pieces of the investigation.

The final results identified fentanyl along with 4-ANPP, alprazolam, methocarbamol and quetiapine as contributing to the fatal toxic effects.

Alprazolam is commonly prescribed under the brand name Xanax and belongs to a class of medications known as benzodiazepines.

Methocarbamol is a muscle relaxant, while quetiapine is a prescription medication used for several psychiatric conditions.

Fentanyl is a powerful synthetic opioid that can be particularly dangerous when taken in combination with other substances that affect the central nervous system.

The coroner’s ruling of accidental death means investigators found no medical evidence that Panettiere intentionally caused her own death.

Emergency Call Came Shortly Before 2 P.M.

Authorities have also provided a clearer timeline of Panettiere’s final afternoon.

At approximately 1:51 p.m. on August 16, emergency dispatchers received a 911 call reporting a cardiac arrest at a residence on Easley Bridge Road in Greenville.

First responders arrived and found Panettiere in cardiac arrest.

Emergency personnel immediately began advanced life-support measures.

They continued attempting to revive her for more than 40 minutes.

Despite those efforts, Panettiere was pronounced dead at 2:32 p.m.

The coroner’s office then began its own investigation alongside Greenville police.

Officials confirmed that Panettiere had been staying temporarily at the residence rather than living there permanently.

No Signs of Trauma or Foul Play

From the earliest stages of the investigation, authorities said they found no indication that Panettiere had suffered injuries suggesting an attack.

The autopsy later reinforced that finding.

A forensic pathologist found no trauma that contributed to her death.

Police also said they had not uncovered evidence of foul play.

Those findings narrowed the investigation toward substances Panettiere may have taken before she became unresponsive.

Her on-again, off-again boyfriend, Brian Hickerson, and his brother Zach were present at the residence when emergency responders became involved.

A police report indicated that Brian directed officers to a bag containing medications that Panettiere had reportedly been taking.

Investigators subsequently began looking more closely at the origins of some of the drugs and pills associated with her final days.

Investigation Expanded Back to Los Angeles

Although Panettiere died in South Carolina, the investigation did not remain there.

Federal drug investigators became involved as authorities examined whether she had obtained controlled substances through sources outside legitimate medical channels in Los Angeles.

Her California residence was searched in late August as part of that inquiry.

Investigators reportedly focused on medications, potential drug-related evidence and communications that could help reconstruct where particular pills came from.

The involvement of federal agents led to widespread speculation that counterfeit prescription medication might have played a role.

At the time, however, Panettiere’s representatives urged the public not to treat preliminary theories as established facts.

The toxicology results now confirm that fentanyl was present and contributed to her death, although the official ruling does not by itself establish exactly where that fentanyl came from or who, if anyone, supplied it.

Questions Remain About the Source of the Fentanyl

The medical findings answer how Panettiere died.

They do not necessarily answer how the substances entered her possession.

That distinction remains important.

Investigators had previously been examining allegations that Panettiere obtained pills through an illicit source.

Reports also suggested authorities were looking into the possibility that a pill she believed to be oxycodone may have contained fentanyl.

The newly released cause of death confirms fentanyl toxicity but does not publicly establish that a counterfeit oxycodone pill was responsible.

Nor does it identify a particular supplier.

Any potential criminal investigation into the source of the drugs would therefore remain separate from the coroner’s medical ruling.

Panettiere Had Spoken Openly About Addiction

The actress had publicly discussed her struggles with alcohol and substance abuse for years.

She said she began drinking heavily while working on Nashville and later entered treatment.

Panettiere also described battling postpartum depression after the birth of her daughter, Kaya, in 2014.

She sought treatment multiple times and later spoke candidly about the toll addiction had taken on her health, career and personal relationships.

In interviews, Panettiere emphasized that treatment was something she had chosen because she wanted to recover.

She rejected the idea that she had simply walked away from motherhood when custody of Kaya shifted to her former fiancé, Wladimir Klitschko.

Panettiere said the decision came during one of the most difficult periods of her life and was made because she believed her daughter needed stability while she focused on recovery.

Her Daughter Remains Central to Her Story

Panettiere welcomed Kaya with Klitschko in December 2014.

The former couple initially raised their daughter together before Kaya began living primarily with her father.

Panettiere remained emotionally connected to her daughter and continued speaking publicly about their relationship.

In one of her final major interviews, she described how painful it was to hear people claim she had simply “given away” her child.

She said that characterization could not have been further from the truth.

Her battle with addiction, she explained, was part of why she believed allowing Kaya to live with her father was the responsible decision at the time.

Kaya is now one of the family members carrying Panettiere’s legacy forward.

Her Brother’s Death Had Deeply Affected Her

Panettiere had also endured another devastating loss several years before her own death.

Her younger brother, actor and artist Jansen Panettiere, died unexpectedly in February 2023 at age 28 from complications related to an enlarged heart.

Hayden later spoke about the profound impact his death had on her.

She described Jansen as her only sibling and said losing him changed her emotionally and physically.

Although she continued working, writing and appearing publicly, she said the grief remained constant.

Her struggles with grief became part of the deeply personal story she increasingly shared with fans.

A Career That Began Before She Could Remember It

Panettiere spent nearly her entire life in entertainment.

She began appearing in commercials as a child before moving into television and film.

Her breakthrough roles included Sheryl Yoast in Remember the Titans and Claire Bennet, the indestructible cheerleader at the center of Heroes.

She later starred as country singer Juliette Barnes on Nashville, a role that earned her multiple award nominations.

Panettiere also became a recognizable face of the Scream franchise as Kirby Reed.

Her performances often projected toughness and confidence, even as her private life became increasingly complicated.

Final Ruling Brings Medical Clarity, but Other Questions Remain

For more than a month, Panettiere’s official cause of death remained unknown.

The autopsy found no fatal injuries.

Authorities found no signs of foul play.

Toxicology testing was still underway.

Now that uncertainty has ended.

Hayden Panettiere died from the combined toxic effects of fentanyl and several other medications, and authorities have classified her death as accidental.

But the ruling does not close every question surrounding her final days.

Investigators may still determine where the fentanyl came from, whether Panettiere knew she was taking it and whether another person could face legal consequences for supplying any substance involved.

Those answers belong to the continuing investigative process.

The medical question, however, has now been settled.

More than a month after the actress died at just 36, officials have finally explained what happened inside her body during her final hours — bringing clarity to one part of a tragedy that continues to leave her family, friends and fans with an enormous loss.