Masood 55, was born in Adrian Elms, and was shot dead by police. He had not been a subject of any police onvestigations, BBC reported.
Three women and five men were arrested in London and Birmingham on suspicion on preparation of terrorist acts following Wednesday’s attack.
PC Keith Palmer, 48, Aysha Frade and US tourist Kurt Cochran, 54, were killed on Wednesday, while a 75 year old man died on Thursday evening.
The so called Islamic state group has said it was behind the attack.
Masood drove into pedestrians on Westminster bridge, before crashing his car into railings, and when running into grounds of Parliament, armed with a knife.
He stabbed PC Palmer before being shot dead.
The Metropolitan police said that there has been no prior intelligence about Masood’s intention to carry out attacks.