Actress Hayden Panettiere, known for her roles in "Nashville" and "Heroes," died unexpectedly at the age of 36, her father announced Sunday. She was found dead in an apartment in Greenville, South Carolina, after a friend reported an unresponsive female in cardiac arrest.

Paramedics attempted resuscitation efforts, but Panettiere was pronounced dead at the scene. Preliminary investigations have not revealed any signs of foul play or suspicious circumstances, according to local police. An autopsy is scheduled to determine the official cause of death.

Panettiere, who was days away from her 37th birthday, had a public battle with addiction and postpartum depression. She previously shared that her struggles with drugs and alcohol escalated as she got older, and in 2015, she sought treatment for postpartum depression after welcoming her daughter, Kaya, with ex-fiancé Wladimir Klitschko. She also voluntarily entered a treatment center in 2020, where she spent eight months receiving care. In her memoir, "This is Me: A Reckoning," she recounted doctors warning her that she risked dying within five years if she did not stop drinking.

Her death comes over three years after her brother, Jansen Panettiere, died unexpectedly in February 2023 from an undiagnosed heart condition. At the time of his death, she described him as her "only sibling" and stated that losing him felt like losing "half of my soul."

Panettiere's career began in infancy with toy train commercials, but she gained widespread recognition at 16 for her role as Claire Bennet in the NBC series "Heroes." She later starred as Juliette Barnes in the country music drama "Nashville."

Her relationship with Brian Hickerson, which was on and off between 2018 and 2022, was marked by multiple domestic violence incidents. In April 2021, Hickerson was sentenced to 45 days in county jail after pleading no contest to two felony counts of injuring a spouse or girlfriend. He was also placed on probation, ordered to attend domestic violence classes, and received a five-year restraining order against Panettiere.

Panettiere's last social media post, made about two weeks before her death, showed her at a gathering with friends. Her most recent public sharing of her memoir, "This is Me: A Reckoning," in May, focused on her journey and her relationship with her daughter.