Hayden Panettiere died after taking just one pill that is believed to have been oxycodone laced with fentanyl, it was reported Monday as cops are said to be zeroing in on her alleged drug dealer.

The actress appears to have met with her “long-term drug dealer” in Los Angeles before flying to South Carolina, where she died of a suspected overdose on Aug. 16, just before her 37th birthday, multiple law enforcement sources connected to the case told TMZ.

The mom appears to have taken one pill the day she died, but it was fatal because it was laced with fentanyl, the sources said of the opioid 50 times stronger than heroin.

Panettiere died from a suspected overdose but the authorities have not released her exact cause of death. They warned t

The development comes amid reports that the authorities were “zeroing in on a potential drug dealer” in the case. Toxicology reports could take up to twelve weeks.