Image copyright CBS Image caption Saoirse Kennedy, 22

Saoirse Kennedy Hill, the granddaughter of assassinated presidential candidate Robert F Kennedy, has died.

Emergency services were called to the Kennedy residence in Hyannis Port, Massachusetts on Thursday. The 22-year-old was pronounced dead at Cape Cod Hospital.

She was the daughter of Robert and Ethel Kennedy's fifth child, Courtney.

The Kennedy family has seen a number of tragedies including the assassination of Saoirse's grandfather in 1968.

His murder came only five years after the assassination of his brother, President John F Kennedy, whom he had served under as US attorney general.

"Our hearts are shattered by the loss of our beloved Saoirse. Her life was filled with hope, promise and love," the family said in a statement.

A statement from her grandmother added: "The world is a little less beautiful today."

Ms Kennedy Hill was the only daughter of Courtney and Paul Michael Hill. Mr Hill is one of four people wrongly convicted of an IRA pub bombing in 1974, who were collectively known as the Guildford Four.

No further details about her death have been released, although US media report she died of an apparent drug overdose.

The 22-year-old was a communications major at Boston College, according to the New York Times, and had suffered from depression.

"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 student newspaper in 2016.

Image copyright Getty Images Image caption Emergency services were called to the Kennedy compound on Thursday

In 2007, People magazine reported that police investigated a kidnapping attempt against the then-10-year-old as she walked home from playing tennis in Cape Cod.

She told police that two men with a white van offered her a ride, but she ran away, the magazine reported at the time.

Police said they were called to a report of "an unattended death" and have launched an investigation.

The compound was the summer White House for John F Kennedy in the 1960s. He was assassinated in Dallas in 1963.

July marked 20 years since the death of President Kennedy's son, John F Kennedy Jr. He was piloting a light aircraft to a wedding at Hyannis Port, but crashed into the sea en route.

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Other Kennedy family tragedies