The investigation into actress Hayden Panettiere’s sudden death has taken a major turn, with law enforcement sources indicating she may have ingested a single oxycodone pill contaminated with fentanyl.

Panettiere, 36, died on August 16 after being found unresponsive at a temporary residence in Greenville, South Carolina.

Authorities now believe the fatal pill could have originated from a long-term Los Angeles drug supplier. The Drug Enforcement Administration is working to trace the pill back to its source.

Multiple law enforcement sources connected to the case stated Panettiere took an oxycodone pill on the morning of her death and that it was contaminated with fentanyl. These sources also reported she had allegedly acquired several black-market prescription drugs from a longtime dealer in Los Angeles prior to traveling to South Carolina.

DEA agents in Los Angeles are currently piecing together Panettiere’s relationship with that alleged supplier and attempting to trace the suspected fatal pill. Investigators are also conducting inquiries in South Carolina.

However, toxicology results remain pending. The current understanding among investigators describes the fentanyl-laced pill as their working theory, not a final conclusion from the coroner.

A police report indicated Panettiere’s on-again, off-again boyfriend, Brian Hickerson, and his brother were present at the apartment when she died. According to reports, Hickerson showed an officer a bag containing medications Panettiere was taking.

The Greenville County Coroner’s Office reported that the autopsy found no signs of trauma contributing to her death and that the official cause and manner of death would remain pending until additional studies are completed.

Panettiere became a star at a young age, playing football-loving Sheryl Yoast in Remember the Titans before gaining wider recognition as Claire Bennet on Heroes and Juliette Barnes on Nashville. She had previously spoken publicly about her struggles with alcohol and opioid addiction, postpartum depression, and recovery. Her memoir, This Is Me: A Reckoning, was published only months before her death.

The suspected involvement of a fentanyl-laced counterfeit pill underscores the devastating consequences of illicit drug markets, where one dose can become fatal. It also explains why investigators are focusing on tracing the supply chain in Los Angeles rather than solely examining the scene in South Carolina.

For now, the strongest available evidence points to a single oxycodone pill laced with fentanyl as the potential cause of death. The final medical determination remains pending once toxicology results are complete.