A woman walks by a poster of a missing man in the London Bridge area of London on Tuesday, June 6, 2017. A new search was underway Tuesday in a neighborhood near the home of two of the London Bridge attackers, hours after police said they had freed everyone detained in the wake of the Saturday evening rampage that left several dead and dozens wounded. (AP Photo/Matt Dunham)

The family of an Australian nurse who was one of the seven people killed in the London Bridge extremist attacks said Tuesday that she died while trying to assist other victims of the van and knife rampage.

London's Metropolitan Police issued a statement from the family of 28-year-old Kirsty Boden praising her compassion and natural instinct to help.

"As she ran towards danger, in an effort to help people on the bridge, Kirsty sadly lost her life," read the statement, which went on to say that Boden's actions "demonstrate how selfless, caring and heroic she was, not only on that night, but throughout all of her life."

Police have not elaborated on how Boden died. Australian media reported that she was from Loxton in southern Australia.

The Islamic State group has claimed responsibility for the brazen attacks that started on the bridge, where three attackers drove a rented white van onto a sidewalk and into pedestrians. Then, armed with knives and wearing fake suicide vests, they charged through Borough Market, an old-fashioned outdoor food market surrounded by bars and restaurants that come alive at night.

At least 48 people were injured, nearly half critically, in Saturday night's attacks. As of Tuesday, friends and relatives were becoming increasingly desperate to learn the fate of others still missing.

Police said Tuesday that a French man who has been missing since the night of the attack may have been thrown off London Bridge and into the River Thames by the killers' speeding vehicle.

The Metropolitan Police force appealed for information about 45-year-old Xavier Thomas, who was walking with his girlfriend over the bridge when the attack began on Saturday night. Thomas' girlfriend was struck and seriously injured by the van.

The force said witness accounts suggest he might have been thrown into the river. Boats from the police marine unit and the Royal National Lifeboat Institution have been searching the river.

Another Australian woman, 21-year-old Sara Zelenak, also has been missing since the attack. Her family is pleading for information and raising money to fly her parents to Britain, where Zelenak worked as a nanny.

Her mother, Julie Wallace, told Brisbane radio station 97.3FM that the family had planned to meet Sara in Europe soon.

"We were counting down the days to see her," Wallace said. "The last time I spoke to her was our time Friday afternoon at 4:42 and she said, 'Oh mum! It's only 28 days until you and I and dad can have baguettes and cheese and croissants in Paris.'"

A woman named Tara who identified herself as Sara Zelenak's aunt said the family is "bracing for the worst." Speaking to media Tuesday outside the family's home in Ormiston in eastern Australia, the aunt called Zelenak a "special, kindred spirit."

Ignacio Echeverria, a 39-year-old Spanish banker, also remains missing after trying to help a woman injured in the vicinity of Borough Market, his father said, based on the account of a friend of Echeverria's who was at the scene. The friend described seeing Echeverria lying on the floor after confronting one of the assailants.

The father, Joaquin Echeverria, told The Associated Press that the family was flying to London on Tuesday to join other relatives. Echeverria's brother, Joaquin, told the AP on Tuesday that British authorities told the family it would be another 24 to 48 hours before they could confirm whether Ignacio was among the dead.

The sister of missing 32-year-old James McMullan, who is British, said he is believed to have died in the attacks because his bank card was found on one of the bodies. Melissa McMullan said authorities would not be able to formally identify him until a coroner's report was released.

Police have identified Canadian Christine Archibald, a 30-year-old social worker who worked at a homeless shelter before moving to Europe to be with her fiance, as among the dead.

Australian Foreign Affairs Minister Julie Bishop said in a news release that the government has confirmed that two Australians were killed, but was awaiting official confirmation of the victims' identities before releasing their names.


Associated Press writer Angela Charlton reported from Paris and AP writer Tammy Webber reported from Chicago. AP writers Aritz Parra in Madrid and Jill Lawless in London contributed to this report.