Hayden Panettiere, who broke through as the seemingly indestructible cheerleader Claire Bennet on NBC’s “Heroes,” died Sunday, Aug. 17, at a residence in Greenville, South Carolina, according to ABC News. She was 36.

Emergency responders found her in cardiac arrest and attempted advanced cardiac life support, but resuscitation was unsuccessful, according to the Greenville County Coroner’s Office, as reported by ABC7 Chicago. The coroner’s office said no signs of trauma were discovered, and that the official cause and manner of death remain pending further investigation and additional studies. Her father, Skip Panettiere, released a statement calling her “an incredible light and a force of nature who brought immeasurable love and joy to all who knew her — and to the millions who watched her onscreen,” per ABC News.

Key Points

• Panettiere died Sunday, Aug. 17, at age 36; a cause of death has not been determined, per the Greenville County Coroner’s Office.
• She starred as Claire Bennet on NBC’s “Heroes” (2006-2010), a four-season ensemble drama built years before shared cinematic universes became standard.
• Before “Heroes,” she appeared in 2000’s “Remember the Titans” and voiced a role in Pixar’s “A Bug’s Life.”
• She later led “Nashville” as Juliette Barnes and returned to the “Scream” franchise as Kirby Reed.

“Heroes” premiered on NBC in 2006, created by Tim Kring, and followed strangers scattered around the world who begin discovering they have superhuman abilities and must find each other before disaster strikes. It ran four seasons and pulled in more than 10 million viewers an episode across its first two, according to NBC’s own account of the series, arriving well before the interconnected, multi-character format became the industry default.

Panettiere was 16 when she was cast. Claire’s introduction in the pilot, jumping off a water tower and healing on impact, gave the show its tagline: “Save the cheerleader, save the world.” She wasn’t a newcomer to the role; she’d already spent a decade working, including a stint on the soap “Guiding Light” and her turn in “Remember the Titans,” according to IBTimes UK.

Life After Claire Bennet

Once “Heroes” ended, Panettiere didn’t retreat into one lane. She spent six seasons as country singer Juliette Barnes on “Nashville” and stepped back into horror as Kirby Reed for the revived “Scream” franchise, roles that showed off a range the cheerleader part never had room for, per ABC News.

If you were watching NBC on Monday nights in the fall of 2006, “Heroes” is probably the reason you know what a “graphic novel within the show” is, or why office-worker-with-a-secret-power became such a durable premise. The series didn’t invent the idea of ordinary people with extraordinary abilities, but it proved a network audience of millions would follow a sprawling cast across a shared timeline toward one converging threat — the exact structure that would come to define superhero storytelling on television for the next two decades. Panettiere’s Claire, the girl who couldn’t be hurt, ended up being the character most people remember first.