A private funeral mass was held on Monday for the 22-year-old granddaughter of Robert F. Kennedy, who died last week after being found unresponsive at the family's compound in Hyannis Port, Massachusetts, a family spokesman said.

Saoirse Kennedy Hill was laid to rest following the mass at Our Lady of Victory Church in Centerville, Massachusetts, Kennedy family spokesman Brian O'Connor said.

Her parents and 91-year-old grandmother, Ethel Kennedy, attended the closed service in Centerville, southeast of Boston on Cape Cod, along with members of the extended Kennedy clan, local media reported.

Hill was rushed to Cape Cod Hospital shortly after 3 p.m. EDT (1900 GMT) on Thursday after she was found unresponsive at the Hyannis Port estate. She was later pronounced dead.

An autopsy found no trauma to the young woman's body, leaving the cause and manner of her death to be determined following toxicology tests, the local district attorney's office said on Friday.

The New York Times, citing two unnamed people described as close to the Kennedy family, reported that Hill was believed to have died of a drug overdose.

Hill was a student at Boston College, where she was a communications major and vice president of the Student Democrats, according to the Times.

Saoirse Kennedy Hill was laid to rest following the mass at Our Lady of Victory Church

The newspaper said she had written about struggling with depression while a student at a private preparatory school in Massachusetts in 2016.

Hill's grandfather, then a U.S. senator from New York, was shot to death in Los Angeles just after winning the California primary race for the Democratic presidential nomination in 1968.

His older brother, President John F. Kennedy, was himself assassinated in 1963 in Dallas.