According to the mother of 22-year-old Zaghba, he became radicalised online, echoing concerns raised by Prime Minister Theresa May that the internet can be fertile ground for breeding extremism.”We have always been checking his friendships and verifying that he was not trusting the wrong people, but he had the internet and from there he got everything,” Valeria Khadija Collina told L’Espresso in Bologna.Zaghba was stopped at Bologna’s airport trying to fly to Turkey in March last year over concerns he was intending to travel on to Syria, according to reports. Zaghba, Pakistan-born British citizen Khuram Shazad Butt, 27, and Rachid Redouane, 30, who claimed to be Moroccan-Libyan, launched a murderous rampage around London Bridge and Borough Market on Saturday night. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. A Metropolitan Police spokesman said: “Detectives investigating the London Bridge terror attack have carried out a search warrant at an address in east London in the early hours of Wednesday June 7.”Officers from the Met’s Counter Terrorism Command, supported by officers from the Territorial Support Group, entered the address in Ilford at around 1.30am.”A 30-year-old man was arrested on suspicion of the commission, preparation or instigation of terrorist acts (contrary to section 5 Terrorism Act 2006) and has been taken into custody at a south London police station under the Terrorism Act 2000. The youngest of Saturday’s attackers is said to have told Italian authorities “I’m going to be a terrorist”, while officers reportedly found Islamic State-related material on his mobile phone when they intercepted him.Counter-terror agencies are already facing intense scrutiny after it was revealed Butt had been known to security services.In other developments:There were fears for missing French national Xavier Thomas, 45, who police said could have been thrown into the River Thames after being struck by the van.The Metropolitan Police said all of the 15 victims currently in critical care had been identified, as public appeals continued for several people who have not been located since the attack.Detectives arrested a 27-year-old man under the Terrorism Act at an address in Barking, east London, shortly after 8am on Tuesday, while search warrants were also executed at addresses in Barking and Ilford.A man in his 30s was arrested by Irish police in Wexford county, south of Dublin, and questioned over documentation connected to Redouane.The arrest took the total number held as part of the investigation to 15, with 12 released without charge.Claims emerged that Butt was reported to counter-terrorism authorities almost a year before the deadly attack after a “violent scuffle” with a member of an anti-extremism organisation.Borough High Street and the roads and area east of the high street reopened to the public, although Borough Market and a small surrounding area remain closed. 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 30-year-old was held on suspicion of the commission, preparation or instigation of terrorist acts during a search of a property in Ilford and taken for questioning at a south London police station, Scotland Yard said.The arrest comes as security services face growing questions over their monitoring of the three attackers in the lead up to the attack. A woman places flowers on a memorial for victims in London BridgeCredit:AP Photo/Matt Dunham “A search of the address is ongoing.”On Tuesday the third attacker was named as Youssef Zaghba, an Italian national of Moroccan descent, who was living in east London.