Khalid Masood at school, left and right, and after being arrested for a knife-related incident. Composite: Huntley school/Metropolitan police
Counter-terrorism investigators have been investigating Khalid Masood’s life and associations across Britain as they raced to discover what led him to kill four people and injure more than 50 in Wednesday’s murderous attack in Westminster.
A joint investigation by Scotland Yard’s counter-terrorism command and MI5 led to new arrests on Thursday in London, Birmingham and Manchester with two people still in custody, while properties were searched in Wales and southern England.
Police want to discover if Masood, who was shot dead by armed police, was encouraged, supported or directed in the atrocity. The 52-year-old mowed down people in the heart of London then stabbed a police officer to death as he tried to burst into the Palace of Westminster.
The Guardian understands detectives are scouring large amounts of CCTV camera footage to see if there is any recording of Masood scouting the Westminster area before the attack.
They are also using camera records and automatic number plate recognition technology to see if they show his car in the area, when Masood could have been working out where the best place to run people over might have been and what weak points there were in Palace of Westminster security in the run-up to the attack. They will also repeat the same time-consuming lines of inquiry to see if a possible accomplice may have done the same.
Two minutes before the attack started at about 2.40pm on Wednesday, Masood used the WhatsApp communications app on his mobile phone, although it is not known why.
On Friday police named Masood’s fourth victim as 75-year-old Leslie Rhodes. Two people remained in a critical condition in hospital.
MI5 is urgently trying to discover how someone could come to believe in Islamic State’s violent ideology and hatch a murderous plot against high-profile targets to gain worldwide attention, all without the domestic security service having any idea it was coming.
Fresh details about Masood’s life have emerged. He had a 20-year history of offending that saw him jailed at least twice. He had converted to Islam more than a decade ago, and used several names during his life, having been born as Adrian Elms and brought up as Adrian Ajao before adopting a Muslim name.
So far, police believe he acted alone when he drove a hired car into civilians on Westminster Bridge before running into the grounds of parliament and stabbing a police officer to death. It emerged that on the eve of the attack he had checked into a Brighton hotel under his own name. The hotel manager said that Masood had been “laughing and joking”.
Mark Rowley, Britain’s top counter-terrorism officer, said: “Whilst there is no evidence of further threats, you will understand our determination to find out if he either acted totally alone inspired by terrorist propaganda or if others have encouraged, supported or directed him.”
He described as “significant” two arrests made in Manchester and Birmingham.
Since the attack, police have arrested 11 people on suspicion of preparing terrorist acts. On Friday they released eight without charge, having eliminated them from their inquiries, and one woman was released on Thursday on bail. The two in custody are a 58-year-old man and a man aged 27, both arrested on Thursday in Birmingham.
