The man who mowed down pedestrians and stabbed a policeman in an assault on the heart of British democracy was 52-year-old Khalid Masood, who was born in Kent in southeast England, police said on Thursday.
London’s Metropolitan Police said in a statement that Masood was known by “a number of aliases” and had been living in the West Midlands, which includes the city of Birmingham where there was an armed police raid overnight.
“The man was British born and... some years ago he was once investigated by MI5 in relation to concerns about violent extremism,” Prime Minister Theresa May told parliament on Thursday, adding: “He was not part of the current intelligence picture.”
She said there had been no prior intelligence of his intent nor of the plot.
Meanwhile, British police have arrested seven people in the investigation into an attacker who killed three people and injured about 40 before being shot to death by police, Britain’s most senior counter-terrorism officer said on Thursday.
Mark Rowley said the latest figures were that there were four dead including the attacker and 29 people being treated in hospital, seven of whom were in a critical condition. Police had said late on Wednesday that the death toll was five.
Rowley said police had searched addresses in London, Birmingham and other parts of the country in their investigation.
“It is still our belief ... that this attacker acted alone and was inspired by international terrorism. At this stage we have no specific information about further threats to the public,” Rowley said.

He said there was a mix of nationalities among the dead but gave no details. The victims were a policeman who was stabbed and two members of the public, a woman in her mid-40s and a man in his mid-50s.
The fourth dead was the assailant.
The attack on Wednesday started when the assailant sped across Westminster Bridge in a car, ramming pedestrians along the way. He then ran towards parliament and stabbed the policeman before he was shot.
Three French high-school students aged 15 or 16, who were on a school trip to London with fellow students from Brittany, were among the injured.

French Foreign Minister Jean-Marc Ayrault was expected to arrive in London to visit them at hospital, French media reported.
Westminster Bridge remained cordoned off with a strong police presence. The nearby Westminster underground train station, normally a busy hub in the morning rush hour, was not accessible from street level as it was within the cordon.
Parliament was due to convene later in what Prime Minister Theresa May said late on Wednesday was a sign that the attack would not disrupt British democracy or normal life in the capital.
Car rented from Birmingham
The car which an attacker used to plough into pedestrians on London’s Westminster Bridge killing two people on Wednesday had been rented from Birmingham in central England, hire firm Enterprise said on Thursday, reported Reuters
“We can confirm that the car used in the tragic attack in London yesterday afternoon was one of ours,” said a spokesman for Enterprise Holdings, adding it had been hired from its Spring Hill branch in Birmingham.
“An employee identified the vehicle after seeing the licence plate in an image online. We ran another check to verify, and immediately contacted the authorities. We are co-operating fully with the authorities and will provide any assistance that we can to the investigation.”
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