Fears are also growing for 45-year-old Xavier Thomas, who has not been seen since Saturday night.
Boats from the police marine unit and the Royal National Lifeboat Institution have been searching the river since the attack.
The police have come under scrutiny following the identification of the attackers because one of them was known to the authorities.
He appeared in a Channel 4 documentary called "The Jihadis Next Door" a year ago and was once asked to leave a mosque in east London for being disruptive.
If confirmed, Thomas would be the eighth person killed in the vehicle and knife attack.
Zaghba visited her at her home near Bologna several times and in March 2016, after being stopped at Bologna airport, he was investigated for possible worldwide terrorist activity but released, according to the newspaper.
Police have named Youssef Zaghba, a 22-year-old Moroccan-Italian man who lived in east London, Khuram Butt, 27, from Barking, and Rachid Redouane, 30, who also lived in Barking, as the men who carried out the attack. Butt was previously known to security agencies and had appeared in a British TV documentary called "The Jihadis Next Door".
A CNN report has since claimed that he was on the watchlist of Italy after being "stopped at the Bologna airport by Italian airport police in March 2016 as he was trying to board a plane bound for Istanbul".