Image copyright Getty Images Image caption Maeve Kennedy McKean, pictured here with her husband and their children, went missing on Thursday

The body of Maeve Kennedy McKean, granddaughter of assassinated presidential candidate Robert F Kennedy, has been found in Maryland.

The 40-year-old and her eight-year-old son were last seen on Thursday evening riding in a canoe off Chesapeake Bay.

After an extensive search operation, police said on Monday that her body had been found in water about 2.5 miles (4km) south of where they had set off.

Officials will continue looking for her missing son, Gideon, on Tuesday.

Mrs McKean was the daughter of Kathleen Kennedy Townsend, the former Maryland lieutenant governor. She worked as a public health and human rights lawyer and was executive director of Georgetown University's Global Health Initiative.

She had been staying with her family at her mother's house in Shady Side, Maryland, when she went missing.

Her husband, David McKean, said in a Facebook post that they had been "self-quarantining" there away from their usual residence in Washington DC in order to give their children more space.

He said his wife and son had disappeared after attempting to retrieve a ball they had been playing with.

"They got into a canoe, intending simply to retrieve the ball, and somehow got pushed by wind or tide into the open bay," he wrote on Friday. "About 30 minutes later they were spotted by an onlooker from land, who saw them far out from shore, and called the police."

Police said last week that their canoe "appeared to be overtaken by the strong winds".

Officials also confirmed an overturned boat matching its description had been found on Thursday evening, hours after they went missing.

Image copyright Getty Images Image caption Mrs McKean - with her cousin, Congressman Joe Kennedy at a DC rally - is part of the Kennedy political dynasty

Boats, helicopters and underwater sonar technology has been used to help locate the pair.

Kathleen Kennedy Townsend paid tribute to her daughter last week, following news that the rescue operation had become a recovery one.

In a statement, she said her daughter had been "vivid" and had dedicated her life to society's most vulnerable.

"My heart is crushed, yet we shall try to summon the grace of God and what strength we have to honour the hope, energy and passion that Maeve and Gideon set forth into the world," she said in a statement.

Congressman Joe Kennedy, Mrs McKean's cousin, also paid tribute.

David McKean, announcing the family accident on Friday, described his wife as his "everything" and said his young son was both "brave" and "deeply compassionate".

"It is impossible to sum up Gideon here. I am heartbroken to even have to try," he wrote on Facebook. "I used to marvel at him as a toddler and worry that he was too perfect to exist in this world. It seems to me now that he was."

The Kennedy family, an American political dynasty, has been beset by a series of tragedies.

Mrs McKean's grandfather, New York Senator Robert F Kennedy, was assassinated in 1968. His death came less than five years after his brother, President John F Kennedy, was also shot dead.