Investigators looking into Hayden Panettiere’s death are reportedly focusing on a single pill they believe contained fentanyl.
Multiple law enforcement sources with direct knowledge of the investigation told TMZ that Panettiere took what she believed was oxycodone on the morning of Aug. 16, the day she died at age 36. Their working theory is that the pill had been laced with fentanyl.
The Greenville County Coroner’s Office has not announced Panettiere’s cause or manner of death, and toxicology results remain pending. TMZ’s sources themselves cautioned that their theory still depends on those results.
The new report arrives as federal and local investigators try to determine where drugs and medications connected to Panettiere came from. The Los Angeles Times independently reported before TMZ’s latest story that DEA agents and local authorities had been questioning people as part of that effort.
Investigators Believe One Pill Contained Fentanyl
TMZ’s sources allege that Panettiere had been obtaining black-market prescription drugs from a longtime source in Los Angeles before traveling to South Carolina on Aug. 15.
According to the outlet, investigators believe she took several substances she had obtained before or during the trip, then took a pill she believed was oxycodone the following morning. The law enforcement sources said their current theory is that the final pill contained fentanyl.
The report goes further in alleging that DEA investigators in Los Angeles are examining Panettiere’s relationship with the person believed to have supplied the drugs and are attempting to trace the pill back to its source. No supplier has been publicly charged in connection with her death.
The Los Angeles Times had already confirmed that federal and local investigators were examining the origins of controlled substances and medications potentially connected to Panettiere’s death. Its Sept. 11 report said several people had been questioned, but the coroner had not yet determined what killed her.
Her Official Cause of Death Is Still Pending
Panettiere was temporarily staying at a residence in Greenville, South Carolina, when a 911 call reporting cardiac arrest came in at approximately 1:51 p.m. on Aug. 16.
The Greenville County Coroner’s Office said emergency medical personnel initiated advanced cardiac life-support measures but could not revive her. She was pronounced dead at 2:32 p.m.
An autopsy performed the following day found no trauma that contributed to her death. The coroner listed both the cause and manner as pending further investigation and additional studies.
A police report later obtained by the Associated Press confirmed that Panettiere’s on-and-off boyfriend Brian Hickerson and his brother Zach Hickerson were at the residence while emergency personnel attempted to revive her. Police reported no signs of foul play.
The same investigation also documented medications Panettiere had been taking. The Los Angeles Times reported that Brian showed an officer a bag containing her medications, but authorities have not publicly said that anything in that bag was contaminated with fentanyl.
Panettiere Had Spoken Publicly About Opioid Addiction
Panettiere had spent years speaking candidly about addiction to opioids and alcohol, including how those problems developed during different periods of her life.
In 2022, she said someone on her team had begun giving her what she called “happy pills” before red-carpet appearances when she was 15. She told PEOPLE at the time that she had not understood how inappropriate that was or what it could eventually mean for her relationship with drugs.
She later told Women’s Health that an old neck injury eventually led her to opioids. “My tolerance got so high so fast that it became a problem,” she said, describing a period in which she alternated between opioids and alcohol.
Her physical health deteriorated as her drinking worsened. Panettiere recalled developing jaundice, seeing her eyes turn yellow and needing to see a liver specialist. During the promotional run for her 2026 memoir, she revealed that a doctor had warned she could be dead within five years if she did not stop drinking.
She subsequently underwent an extended period of rehabilitation, trauma treatment and 12-step work. PEOPLE reported from her memoir that one intensive rehabilitation stay lasted eight months.
She Had Returned to the Public Eye Months Before Her Death
Panettiere spent much of 2026 speaking more openly about experiences she had previously kept private. Her memoir, This Is Me: A Reckoning, was released May 19 and addressed childhood fame, addiction, postpartum depression, abusive relationships and the death of her younger brother Jansen.
During that promotional period, she appeared in extended television, podcast and print interviews discussing treatment, motherhood and her attempts to rebuild her life. Her May appearance on The Tamron Hall Show included a lengthy conversation about addiction and the experiences detailed in the memoir.
Her acting career had also resumed after several years away from regular screen work. She returned as Kirby Reed in Scream VI in 2023 and starred in the psychological thriller Sleepwalker, released in January 2026.