Investigation Into Hayden Panettiere's Death Expands to Multiple States, Focuses on Drugs

The investigation into the death of actress Hayden Panettiere has become a cross-country effort, with authorities in both Los Angeles and South Carolina involved, according to sources speaking with ABC News.

The probe is concentrating on the types of drugs that may have contributed to her passing and their origins.

Panettiere, who was known for her roles in "Heroes," "Nashville," and "Ice Princess," died on August 16. She was discovered unresponsive and in cardiac arrest at a residence in Greenville, South Carolina. First responders attempted resuscitation, but she was pronounced dead at the scene.