This is the moment an armed police officer trains an assault rifle on the window of a suspect arrested in connection with the Westminster terror attack.
The officer, wearing a balaclava and helmet, is seen in the back garden of a suburban house during a raid in Birmingham yesterday.
The raid was one of a series carried out around the country by anti-terror police after Khalid Masood killed four and injured more than 50 in London on Wednesday.
A total of 11 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.
One of the arrested was Masood's partner Rohey Hydara, 39, who lives at a property in east London's Olympic park.
She has been released on bail until late March.
A neighbour who took the pictures of the armed officer during the raid in Birmingham said: 'I went to my window and there three cops with guns running up to the back window.
'There was shouting and screaming for ages, I couldn't hear what they were saying but it was proper loud. It sounded like there were loads of people in there.'
The neighbour added: 'They just stood there for like an hour or 45 minutes. I think they were making sure that no one was going to try and escape round the back or anything like that.
'I had no idea what the hell was going on and now people are saying it's something to do with the attack in London.'
A number of local residents said they believe a man from Saudi Arabia lived at the house in the Winson Green area with his wife and children.
Local resident Shekila Sahota, said a man, thought to be in his 40s or 50s, had lived at the address for about a year.
She added: 'The man they led away was put in the van straight away and he had a big smirk on his face when they took him away.'
The raid came ahead of the arrest of two more 'significant' suspects this morning as police try to find out whether terrorist killer Khalid Masood was aided by others.
Two people, a man and a woman, were arrested in Greater Manchester in the early hours of this morning and another man, aged 27, was arrested in Birmingham.
Police confirmed a 34-year-old man was arrested in a mews road in the affluent West Didsbury suburb of Manchester in the early hours of this morning.
Residents who live close to the affluent gated community, where properties are believed to sell for up to £500,000, said a car had been towed from the area.
The Met's top anti-terror officer Mark Rowley said police have searched 21 properties around the country, with five searches ongoing this morning, and seized 2,700 items including numerous computers.
Masood, 52, killed 75-year-old Londoner Leslie Rhodes, US tourist Kurt Cochran, 54, and mother-of-two Aysha Frade, 43, as he ploughed into pedestrians on Westminster Bridge. He then stabbed PC Keith Palmer, 48, to death inside the grounds of Parliament.
Scotland Yard have also urged anyone who knew Masood or has any information about him to come forward.
Asked about where the Muslim convert had been radicalised, Mr Rowley said: 'As I have said, our investigation focuses on understanding his motivation, preparation and associates.
'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.
'To that end in our continuing investigation and ongoing covert activity we have made further significant arrests overnight - in the West Midlands and North West.'
Mr Rowley said officers had spoken to around 3,500 witnesses - including 1,000 who were on Westminster Bridge and around 2,500 who were in Parliament.
He added: '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 be people out there who did have concerns about Masood but did not feel comfortable for whatever reason in passing those concerns to us.'
Asked whether Masood had travelled overseas, Mr Rowley said 'we are looking at his history'.
Separately from the arrests in the Midlands and North West, police were last night searching a flat in east London which previously housed teams during the 2012 Olympic Games.
It is believed the property was home to a Rohey Hydara, who is believed to have lived with Masood in at least three separate addresses.
Last night, the Met said Masood's partner Hydara, 39, was released on bail pending further inquiries. She was arrested on suspicion of preparing terrorist acts.
Officers could be seen rifling through rooms on the first floor flat, although curtains in most of the windows were drawn.
Residents of the nine-storey block near to the Eurostar Stratford International Station said police had been in the building all day.
Neighbours said they saw Masood at the apartment several weeks ago.
Local resident Vera Amade, 21, said: 'My brother saw him a few times quite recently in the last few weeks.
'It was definitely him, the woman has two kids, one of the daughters has just had a baby. They all live in the same flat.
'She was quite polite, there was nothing bad to say about her. He was really nice and polite as well, he was very pleasant.
'I'm very shocked. We were watching it on TV last night and trying to figure out if it was definitely him and it is.
'He was always dressed in a suit, I don't know what he did for a living. He used to come back from work at about five or six.'
Masood was registered to two addresses in Luton in 2010 and 2011 and was recorded as living in Forest Gate, east London, last year.
Hydara was also registered as having lived at those three places.
A neighbour said three children lived in the home in Forest Gate with their mother, aged between eight and 15.
He said they later moved out to the Olympic Village.
The man, who did not want to give his name, said: 'There was a family who lived here and then they moved out.
'They were there about five, six years. I only saw the kids and the mother.
'We saw the family there, we saw the ladies there but I never saw a man living there. I think he was clean shaven when I did see him last year.
'He was darker, seemed a bit plump. But he was cleanly shaven. I occasionally saw him, I just assumed he was working all day.'