The third London Bridge attacker has been named as Youssef Zaghba, a Moroccan-Italian man.
BBC reports that Pakistan-born Khuram Butt, 27, and Rachid Radouane, 30, both from Barking were the other two attackers.
Meanwhile, another victim has been named as Australian Kirsty Boden, who her family said ran towards London Bridge in an effort to help people.
Seven people were killed and 48 injured in the attack which began at 21:58 BST on Saturday night.
NHS England said 36 people remained in hospital, with 18 in a critical condition.
Butt and his two accomplices drove a hired van into pedestrians on London Bridge before stabbing people in the area around Borough Market.
All three men were shot dead by police within eight minutes of receiving a 999 call.
All 12 people arrested on Sunday after the attack have now been released without charge, but the Metropolitan Police said a 27-year-old man has been arrested in Barking on Tuesday in connection with the incident.
A property in Ilford, east London, was also searched by police at around 01:30 BST, but no arrests had been made, the Met said.