Two members of the Kennedy family are now thought to have died after they went missing on a canoeing trip in Maryland.

The search for Maeve Kennedy McKean, granddaughter of former US attorney general and presidential candidate Robert Kennedy, and her son Gideon was suspended 26 hours after they were last seen in Chesapeake Bay near Annapolis.

The Coast Guard responded to a report from a passer-by that "two individuals were seen struggling to return to shore in a canoe" near Herring Bay on Thursday afternoon.

An upturned canoe matching the description of the one Ms McKean, 40, and eight-year-old Gideon were in was found on Thursday night.

Ms McKean's husband, David McKean, wrote on Facebook that he believed both his wife and son had died.

A Day That Shook The World: John F. Kennedy assassinated Show all 8 1 /8 A Day That Shook The World: John F. Kennedy assassinated A Day That Shook The World: John F. Kennedy assassinated President John F. Kennedy (1917 - 1963) and his wife Jacqueline Kennedy ride with secret agents in an open car motorcade shortly before the president was assassinated in Dallas, Texas, November 22, 1963. Getty Images A Day That Shook The World: John F. Kennedy assassinated Cliff Michelmore pointing to the path of gun shots which killed President John F Kennedy, on a model reconstruction of the Dealey Plaza, Dallas, in the USA. Getty Images A Day That Shook The World: John F. Kennedy assassinated A man holding the rifle used by Lee Harvey Oswald in his assassination of the American President John F Kennedy. Getty Images A Day That Shook The World: John F. Kennedy assassinated circa 1965: The Texas School Book Depository at Dallas, Texas, from which US president John F Kennedy is thought to have been shot. Getty Images A Day That Shook The World: John F. Kennedy assassinated 23rd November 1963: A woman buys a newspaper from a street vendor for the latest headlines concerning the assassination of John F Kennedy. Getty Images A Day That Shook The World: John F. Kennedy assassinated The family and friends of the assassinated American President John F Kennedy (1917 - 1963) mourning his death. Getty Images A Day That Shook The World: John F. Kennedy assassinated Members of the Kennedy family at the funeral of assassinated president John F. Kennedy at Washington DC. From left: Senator Edward Kennedy, Caroline Kennedy, (aged 6), Jackie Kennedy (1929 - 1994), Attorney General Robert Kennedy and John Kennedy (1960 - 1999) (aged 3). Getty Images A Day That Shook The World: John F. Kennedy assassinated 22nd November 1963: US statesman John F Kennedy, 35th president of the US, and his wife Jackie Kennedy travelling in the presidential motorcade at Dallas, before his assassination. Getty Images

He said: "It is clear that Maeve and Gideon have passed away. The search for their recovery will continue, and I hope that that will be successful. At this time, our family asks for privacy and that everyone keep Maeve and Gideon in their prayers.

"It is impossible to sum up Gideon here. I am heartbroken to even have to try. 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."

Mr McKean said of his wife that "she was my everything. She was my best friend and my soulmate."

Commander Matthew Fine of the Sector Maryland National Capitol Region command centre, said: "This was a difficult case, and even more difficult to make the decision to suspend the search.

"Our crews and partners did everything they could to find them. We've kept the family informed at every step during the search, and our thoughts are with them tonight."

A Maryland Natural Resources Police spokeswoman said the search for the pair was scheduled to resume on Saturday morning.

The Kennedy family has become synonymous with high profile tragedies since the assassinations of President John F Kennedy in 1963 and of his brother Robert five years later.

John F Kennedy Jr, son of the former president, died in a plane crash with his wife, Carolyn Bessette, and sister-in-law Lauren Bessette in Massachusetts in 1999.

In 1984 Robert Kennedy's son, David Kennedy, died of a drug overdose in Palm Beach aged 28. His brother Michael died in a skiing accident in Colorado in 1997.

Edward Kennedy, who served as a Massachusetts senator for 46 years, was involved in a car crash at Chappaquiddick in 1969 in which an aide, Mary Jo Kopechne, was killed. His lack of candour after the incident shadowed him throughout his career.

Last year Saoirse Kennedy Hill died of a drug overdose aged 22.