An investigation is now on going in the death of Hayden Panettiere. The DEA has joined the investigation into the death of actress Hayden Panettiere, according to a report by ABC News. Panettiere was found unresponsive at an Airbnb in Greenville, South Carolina, on Sunday. The Greenville Police Department responded to a 911 call reporting Panettiere in cardiac arrest, possibly due to an overdose. Despite extensive efforts by EMS personnel, she was pronounced dead at 2:31 p.m. The investigation remains open, with no definitive cause of death released.