Hayden Panettiere died after taking a pill that multiple law enforcement sources believe contained oxycodone mixed with fentanyl, according to TMZ reporting about the morning she was found unresponsive in South Carolina. Toxicology results were still pending, meaning the suspected cause remained an investigative theory rather than a confirmed finding. According to the report, investigators were examining Panettiere's connection to a longtime Los Angeles drug dealer who allegedly supplied black market prescription medication. Sources said Panettiere took several drugs during a flight from Los Angeles to South Carolina the day before her death, then authorities believed she took an oxycodone pill the following morning. What Are Investigators Looking Into? The Drug Enforcement Administration was reportedly investigating in both Los Angeles and South Carolina, with agents working to determine whether the suspected pill could be traced to the alleged supplier. When first responders arrived at the condo where Panettiere was staying, Brian Hickerson reportedly gave them a bag containing her prescription medications and said he had administered Narcan before paramedics arrived. The circumstances drew comparisons to the case involving Mac Miller , whose drug supplier was convicted after the rapper died from counterfeit medication containing fentanyl. Investigators cautioned that Panettiere's toxicology results would be central to determining what happened and whether any criminal case could follow.