Hayden Panettiere's father was reportedly still coping with the loss of his son when his actress daughter was found dead on Sunday, according to neighbors.

Panettiere, 36, was pronounced dead at an Airbnb in Greenville, South Carolina. Her death occurred three years after her younger brother, Jansen, died at age 28 in February 2023 from complications related to an enlarged heart.

Neighbors told the New York Post that Panettiere's father, Alan 'Skip' Panettiere, had largely withdrawn from his community in Piermont, New York, after his son's death. He had only recently begun to emerge from his grief when he received news of his daughter's passing. Panettiere had visited her father in New York the month prior to her death.

A friend of the actress, Erick Orellana, told Page Six that Panettiere had been planning a vacation to see her 11-year-old daughter, Kaya, who lives in Ukraine with her father, Wladimir Klitschko. "She was talking about how she wanted to take a vacation and that she wanted to go and see her daughter," Orellana said, emphasizing that her daughter was always her "absolute priority."

Authorities have not yet released an official cause of death. An audio recording of a 911 call from Sunday afternoon described the actress as suffering from cardiac arrest, with a dispatcher later noting a suspected overdose. The Greenville County Coroner's Office has completed an autopsy, stating that no signs of trauma were found. Further investigation is underway.

Panettiere had a history of addiction, beginning in her teenage years. She spoke in a 2022 interview about her ongoing struggle with sobriety, describing it as an "everyday battle." Her addiction reportedly worsened during her battle with postpartum depression after Kaya's birth in 2014. Despite entering treatment, she felt the underlying depression was not adequately addressed.

Her memoir, "This Is Me: A Reckoning," released in May, details her separation from her daughter and the emotional toll it took. Panettiere wrote about the "gut-wrenching experience" of not being with Kaya daily and her grief over not being the mother she aspired to be, though she expressed immense love and gratitude for her daughter.

Panettiere also recounted nearly dying during childbirth, undergoing seven blood transfusions and surgery. She described a period of feeling "nothing" when looking at her newborn daughter and subsequently developing postnatal depression, which led to an alcohol dependency. She expressed a desire for more understanding of postpartum depression at the time to receive help sooner.

Panettiere, who would have turned 37 this Friday, is remembered for her roles as Claire Bennet on NBC's "Heroes" and Juliette Barnes on the ABC drama "Nashville."