Robert F. Kennedy's granddaughter, Saoirse Kennedy Hill, died of accidental overdose

Show Caption Hide Caption Robert F. Kennedy's granddaughter dies at 22. Saoirse Kennedy Hill was the only child of Courtney Kennedy Hill, the fifth of Robert and Ethel Kennedy's eleven children.

Saoirse Kennedy Hill, the granddaughter of Robert F. Kennedy, died of an accidental overdose, Massachusetts law enforcement authorities confirmed Friday.

The toxicology results for Hill, sent via the Cape & Islands District Attorney's Office, revealed methadone and ethanol toxicity as well as other prescription medications were found in Hill's system at the time of her Aug. 1 death.

District Attorney Michael O'Keefe said the conclusions came from the state's chief medical examiner, who also ruled the death accidental.

USA TODAY has reached out to the family for comment.

The 22-year-old died at the Kennedy compound in Hyannis Port, Massachusetts, sending shock waves and adding to a history of tragedies for the famed family.

The Kennedy family, at the time of her death, said in a statement, "Our hearts are shattered by the loss of our beloved Saoirse."

"She lit up our lives with her love, her peals of laughter and her generous spirit," the statement said, noting that Hill was passionate about human rights, women's empowerment and volunteer work in indigenous communities. "We will love her and miss her forever."

Hill was the only child of Courtney Kennedy Hill, the fifth of Robert and Ethel Kennedy's eleven children. Hill's father is Paul Michael Hill, one of four falsely convicted in the 1974 Irish Republican Army bombings of two pubs.

Robert’s widow Ethel, 91, said at the time the "world is a little less beautiful today" following her granddaughter's sudden death.

Hill was a member of Boston College's class of 2020, the university confirmed to the Boston Globe. Before that, she attended Deerfield Academy in Deerfield, Massachusetts, where she opened up about her struggles with mental illness.

"My depression took root in the beginning of my middle school years and will be with me for the rest of my life," she wrote in a 2016 essay for the school's student newspaper. "Although I was mostly a happy child, I suffered bouts of deep sadness that felt like a heavy boulder on my chest."

Saoirse's death added to the compendium of tragedies that have befallen the Kennedy family, exemplifying the so-called "Kennedy curse." Among such tragedies is the assassination of her grandfather, "Bobby" Kennedy, who was killed the same night he won the New York and California presidential primaries in the 1968 election. Bobby's death was preceded by the assassination of his brother, former president John F. Kennedy, in 1963.

Contributing: Cydney Henderson and Vandana Ravikumar