Federal investigators say a trove of text messages between Hayden Panettiere and her alleged longtime drug supplier is now the linchpin of the Drug Enforcement Administration's probe into the actress's death, according to a report published Monday by TMZ and corroborated by outlets including ABC's Charleston affiliate and Yahoo Entertainment.

Panettiere, best known for playing Claire Bennet on "Heroes," was found unresponsive on Aug. 16 at a Greenville, South Carolina apartment and pronounced dead that afternoon, five days before her 37th birthday. Law enforcement sources believe she died after taking an oxycodone pill laced with fentanyl the morning of her death, having carried several black-market pills with her on a flight from Los Angeles the night before.

Texts "About Drugs" Span Years

Sources close to the investigation say Panettiere exchanged messages with a Los Angeles-based dealer for years, continuing right up until the week she died, with the conversations growing specific about purchasing black-market pills.

"There are a slew of messages about drugs," a source told TMZ, describing the exchanges investigators are now combing through as the probe's centerpiece.

DEA offices in both Los Angeles and South Carolina are working the case alongside the Greenville Police Department, with agents attempting to trace the pill Panettiere took that morning back to its source, according to a report from ABC's Charleston station. Her boyfriend, Brian Hickerson, who was present at the apartment when she was found, has since spoken with federal agents and turned over a bag of her medications to police.

The DEA first confirmed its involvement in late August, days after Panettiere's death, when it began working the case jointly with local South Carolina authorities, as Variety reported at the time. Official toxicology results, which will determine the legal cause of death, remain pending.

Investigators have drawn comparisons to the federal case against the dealer who supplied Mac Miller with the fentanyl-laced pills that killed him in 2018 — a prosecution built substantially on text-message evidence that resulted in a 17-year prison sentence. No arrests have been made in Panettiere's case, and further reporting on the timeline indicates neighbors near her former West Hollywood residence had for years described visits from associates carrying small bags, including in the days before her death.

Panettiere had spoken publicly in recent years about a long struggle with substance abuse and addiction, writing candidly about it in her 2026 memoir. Her death set off an outpouring of tributes from former "Heroes" castmates and fellow child stars, several of whom used the moment to spotlight the mental health toll of early fame.

The DEA investigation is ongoing. Agents are continuing to work to identify and trace the source of the fatal pill, and no charges have yet been filed as toxicology results and the broader case are finalized in the coming weeks.