Police in London, who were searching for a French man missing since the attack, said earlier they had recovered a body from the River Thames.
It is thought Mr Thomas was thrown into the river when he was also hit by the van.
The accused however are not connected to the 1 June attack in the United Kingdom capital that left eight people dead, the police said on Thursday.
The van-and-knife attack also injured nearly 50 people who were enjoying their Saturday night in a crowded part of London known for its bars and restaurants.
A third man, aged 29, was arrested at a home in the same area on "suspicion of the preparation of terrorist acts". His girlfriend was struck by the van and seriously injured. Three men deliberately drove a vehicle into pedestrian traffic on London Bridge, before fleeing to nearby Borough Market, where they began stabbing bystanders with long knives.
A man has been arrested on suspicion of terror offences by detectives investigating the London Bridge attack following an early morning raid at an address in east London.
The announcement came as United Kingdom authorities faced new questions over how one of the London Bridge attackers was let into Britain despite being on a security watch list.
The assailants killed eight people and wounded 48 others.
The latest arrests come on the eve of Britain's general election on Thursday, after a political campaign marred by the London attack and a suicide bombing in Manchester last month.
All three suspects were confronted and shot dead by armed officers within eight minutes of being called, police noted.
Italian authorities said Zaghba had been stopped and questioned in Italy but had not been charged with any crime.
Charisse O'Leary, the former partner of attacker Rachid Redouane, said she had "shed many tears" for those caught up in the attack.