British police release image of Westminster terrorist attacker Khalid Masood
Masood was previously known by the names of Adrian Elms and Adrian Russell Ajao, and may also have been known by a number of other aliases.
Detectives are continuing to search two addresses in Birmingham and one in East London linked to the investigation.
Searches of other properties in Brighton, Southeast London, East London, Surrey, Manchester, Carmarthenshire and Birmingham have concluded.
A total of 11 people have been arrested as part of the investigation on suspicion of preparation of terrorist acts.
Ten remain in police custody.
Officers are appealing for more information about Masood.
“Our investigation focuses on understanding his motivation, preparation and his associates,” Acting Deputy Commissioner Mark Rowley told reporters on Friday.
“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.
“At this point I want to appeal specifically to the public. We remain keen to hear from anyone who knew Khalid Masood well, understands who his associates were, and can provide us with information about places he has recently visited.
“There might well be people out there who did have concerns about Masood but weren't sure or didn't feel comfortable for whatever reason in passing information to us.”
MI5 is building a detailed file on Masood’s background and recreating his movements over the last few weeks. So far 2,700 items have been seized and 3,500 witness statements have been taken.
Police have revealed that Masood, born in Kent and reportedly a convert to Islam later in life, was described by police as a criminal with a 20-year record of offending.
He had once been investigated for extremism, but was assessed as low risk. His first conviction was in 1983 for criminal damage and his last conviction was in December 2003 for possession of a knife.
He was married with three children, and had been living with his family in an inner-city suburb of Birmingham, police say.
According to reports, Masood claimed on his CV to have taught English in Saudi Arabia in 2005 and returned to the UK in 2009, where he became a “senior English teacher” at a TEFL college in Luton. In 2012, he reportedly set up an English language tutoring business, named IQRA, based in Birmingham.
The attack saw Masood, 52, mowing down people on Westminster Bridge with a 4x4 vehicle before crashing into the railings in front of the Houses of Parliament.
He then left the vehicle and headed for Parliament with a knife, where he stabbed a police officer to death.
Five people, including Masood, died as a result of the attack.
The four victims were Leslie Rhodes, 75, police officer Keith Palmer, 48, teacher Aysha Frade, 43, and US citizen Kurt Cochran, 54.
At least 50 people were injured with 31 requiring hospital treatment, according to police. Two people remain in a critical condition.