911 audio reveals details of Hayden Panettiere's death

Newly released 911 audio has revealed the moment Hayden Panettiere was found unresponsive by the brother of her on-again, off-again boyfriend, Brian Hickerson.

Zach Hickerson can be heard talking to his brother as the call goes through to 911 dispatch, according to audio obtained by CBS News on Wednesday.

"Oh, God. Oh, my God, Brian. Do like, do CPR or something?"

When the dispatcher answered the phone, Zach explained what happened: "I walked in after church to my brother and his girlfriend's apartment, and he woke up, and his girlfriend, she's unconscious."

The operator asks, "OK, is she breathing?" to which Zach responds, "No, I don't think so. Is she breathing? Hold on. No," he repeats.

The dispatcher then instructs Zach on how to do CPR and later mouth-to-mouth until the paramedics arrive on scene.

"They're here," Zach says as the call ends.

The audio call was released nearly two months after Panettiere was discovered unconscious on 16 August in South Carolina and pronounced dead at the scene. She was 36.

Greenville County Coroner's Office announced the Nashville star's official cause of death on 22 September as "toxic effects of fentanyl, 4-ANPP, Alprazolam, Methocarbamol and Quetiapine."

The manner of her death was determined to be an accident.