Formal identification of the body has not taken place, but the family of 45-year-old Xavier Thomas has been informed of the discovery.
People look at floral tributes on London Bridge, Wednesday, to commemorate the victims in Saturday's attack.
Officials said assailants plowed into pedestrians on London Bridge using a van, then drove to Borough Market, where they attacked people with knives.
One of the three terrorists, slain by British police during a deadly attack in London last Saturday and having double Italian and Moroccan citizenship, had been flagged as a potential threat by Italian security services, Italian media reported Tuesday.
The trio, wearing fake suicide bomb vests, were shot dead by eight officers outside a pub after police opened fire with an "unprecedented" hail of 50 bullets.
Thomas was with his girlfriend Christine Delcros who was also hit and is in hospital in London.
Pakistani-born British citizen Khuram Butt attempted to hire a 7.5 tonne lorry hours before the June 3 attack, although the group used a B&Q van loaded with bags of gravel instead. Witness accounts suggested Thomas might have been thrown into the river, police said.
Metropolitan Police Commissioner Cressida Dick said she wouldn't release further details in what she described as a fast-moving investigation, including whether authorities were familiar with the men before the attack.
A 27-year-old man arrested on Tuesday morning and a 30-year-old man arrested on Wednesday morning are also being held, the Met said.
Prosecutors in Italy say there was not enough evidence to arrest or charge the 22-year-old when he was intercepted at Bologna airport.
A second source said Italian authorities had flagged him up to British authorities after he moved to England past year.
Both lived in the east of London.
"There's an election on Thursday, that's the chance", he said, citing an "appalling" cut in police staffing levels.
Eight killed as storm lashes drought-hit Cape Town
In May, the Western Cape province declared a drought disaster after two reservoirs were already completely dry. Western Cape Disaster Management spokesman James-Brent Styan said flying debris had caused many injuries.
Report of multiple casualties in incident on London Bridge
After that attack, Britain's official threat level from terrorism was raised to "critical", meaning an attack may be imminent. The mayor issued a statement early Sunday in which he urged the public to remain calm as the situation is still unfolding.
Apple iMac gets serious spec boost for 2017
The GPU's powering this beast will be AMD's soon to be released VEGA platform with up to 16GB of VRAM and 400 GB/s of bandwidth. Additionally, the new iMacs, which have 21.5- and 27-inch screens, will get more ports for users to attach accessories.
Liquor Baron Arrives At Kohli's Charity Event In UK
In fact, Mallya's presence forced the Indian team to leave early in order to avoid any controversy, sources said. The Indian cricket team is in the United Kingdom for the ICC Champions Trophy 2017 tournament.
Apple to showcase new features for its gadgets
It's the first time in 15 years that Apple has held its conference in San Jose, the heart of Silicon Valley. The Google Home does similar things but comes with the Google Assistant instead of Siri.
New smart speaker expected as Apple kicks off conference
Be proactive - Use the "Flag as Inappropriate" link at the upper right corner of each comment to let us know of abusive posts. The HomePod speaker stands just under seven inches (18 cm) tall and is covered in fabric mesh that will come in white or gray.