Detectives hunt for possible associates of Westminster killer Khalid Masood
Counter-terrorism detectives are attempting to trace any associates of Khalid Masood as they mount a huge investigation to establish what triggered the terrorist's murderous rampage in Westminster.
Eleven people have been arrested as part of the inquiry but Scotland Yard said only four remain in custody - two men aged 27 and 58 who were arrested in Birmingham on Thursday and a 32-year-old woman and a 35-year-old man who were arrested in Manchester on Friday.
All are being held on suspicion of preparation of terrorist acts.
Six of those arrested have now been released from police custody and face no further action - two women aged 21 and 26 and four men aged 23, 26, 27 and 28 who were all arrested at addresses in Birmingham.
A 39-year-old woman arrested in east London has been released on bail until late March.
