The 18-year-old being held by police on suspicion of planting a bomb on the London underground was arrested two weeks ago at the exact same tube station where the device exploded but released, neighbors have said.
The teen - who is being held after police tracked him to the departures hall at the Port of Dover - is thought to have been a 'problematic foster child' who was raised in Sunbury-on-Thames by Penelope Jones, 71, and husband Ronald, 88.
Serena Barber, 47, who has known the couple all her life and lives in a property backing on to theirs, said: 'They have two boys at the moment, both are foreign. One is very quiet and polite, the other who is 18 is awful.
'I know about two weeks ago he was arrested by police at Parsons Green, for what I don't know and returned back to Penny and Ron. After that Penny said she was going to have to stop caring for him, she couldn't handle him.'
The revelation comes after President Donald Trump tweeted that the 'loser terrorist' behind the latest London attack was 'in the sights of Scotland Yard' - and heaps pressure on the force to reveal whether he was detained and why he was released.
Police said they are 'keeping an open mind' on whether there was more than one person responsible for the Parsons Green bombing.
A home in Sunbury-on-Thames raided by investigators in connection with the attack, which injured 30, is owned Penelope and Ronald, who both have MBEs after raising 268 foster children.
Officers stormed the house on Cavendish Road at 2pm around six hours after apprehending the suspect in the departure lounge of the Port of Dover.
Close friends of pensioners Penny and Ron Jones said the couple - who are widely respected in the local area - were at 'their end' with the teenager.
Around 60 people were evacuated from near the house, where locals claimed 'explosives' were found in the garden. There is no suggestion the Joneses had any knowledge of any alleged wrongdoing at the property.
Metropolitan Police Deputy Assistant Commissioner Neil Basu said earlier: 'At approximately 7.50am local police officers in Kent arrested an 18-year-old man in the departures area of the port in Dover.
'He was arrested on suspicion of being concerned in the commission, preparation and instigation of acts of terrorism and transferred to custody in a police station in London.
'Officers from Kent police had to partially evacuate the port of Dover at 11am this morning. That work is now complete and they have recovered a number of items during that search.'
'At around 1.40pm with the assistance of Surrey Police, we evacuated a house on Sunbury-on-Thames. As a precautionary measure we evacuated the surrounding buildings.
'I want to reassure that community that our experts are quickly and thoroughly searching that address.
'At this stage we are keeping an open mind about whether more than one person is responsible for this attack and we are still pursuing multiple lines of enquiry at pace.'
Deputy Commissioner Basu revealed police have received 180 photos and videos and located 121 witnesses - 100 of whom they have spoken to already.
Sunbury-on-Thames is just a 37-minute train ride from Wimbledon station, where the tube that was bombed yesterday began its journey.
Residents on Cavendish Road were evacuated and asked to find somewhere to stay for the evening. Staines Rugby Club has been set up as a meeting point.
Residents in the outer cordon were allowed home at 8pm after they had given their names and proof of address to police.
They were told once they were in their houses they must stay there unless absolutely necessary, and sign in and out of the cordon until it was lifted if they had to leave.
Residents closer living closer to the house were asked to find alternative accommodation for the night.
Brenda Matthews, 53, was told by police to pack essential items and find somewhere to stay for 12 hours while specialist officers raided the property .
She said: 'I looked out this morning and saw men with bandannas. I asked what was going on and a neighbour told me it was a terrorist raid.
'Everyone knows everyone round here. The house involved is blocked off, police are knocking on doors to try and basically get everyone out and to safety.
'The scary thing is how long have these people been living in this house for? I've lived here seven years.'
Mrs Jones is the governor of a local school and became a foster mother after working in a juvenile prison and was always supported by her husband.
The couple featured in an interview with Elmbridge CAN, a community group which aims 'to build a culture of welcome to refugees' and help settle them in the local community.
The organisation states that Mr and Mrs Jones have been foster parents for almost 40 years and had taken in 268 children - the last eight of which were refugees. It is not clear when the interview was published.
In the interview Mrs Jones said fostering 'had its ups and downs', adding: 'They're all children, it doesn't matter if they're sky blue or with pink dots on them - they just need to be loved.'
Alison Griffiths, a Surrey county councillor who knows Mr and Mrs Jones, said they had two young people staying with them - an 18-year-old and a 22-year-old.
She described Mr and Mrs Jones as 'great pillars of the community', adding: 'They do a job that not many people do.'
Ms Griffiths, 42, said the couple may not be able to return home for days as police continue to search their house.
She said: 'I think they are actually staying with friends of theirs.
'But I spoke to the police officer earlier and he said he doesn't think they will be going home until at least five days because of forensics.'
Mojgan Jamali, who lives on the road where the house was raided this afternoon, said police gave her just 'one minute' to pack her bags, grab her children, and leave her home.
She said: 'We didn't know what was going on. There was a lot of rumours going on, a lot of stories, people saying this and that, but we didn't know.'
Another neighbour, who did not wish to be named, told MailOnline police vehicles swooped on the street as she was making her way to a local Tesco store. We thought it was a drug raid, but the police would not tell us anything.
'We tried driving around but they had blocked of part of the road and they said that we really need to go right down [to the other end of the road].
'When I was leaving they were knocking on all the doors. A police sergeant told us that they had found an explosive device.'
A 32-year-old woman who lives locally told MailOnline she was ordered to leave her mother's house after getting a knock on the door from a police SWAT team.
'My brother got a bang on the door about half past one by a swat team and they were told to leave immediately.
'We are waiting outside on Catherine Drive there now. Everyone is cold and just waiting to see when we can go back home. The couple in the house are lovely, they've be fostering kids for years since I was little.'
A woman, who lives opposite, added: 'I am so worried about Ron and Penny, they are a lovely couple. I hear they have been taken away for questioning. I don't understand.'
At 8.20am on Friday, a bomb left by a suspected terrorist detonated on the tube at Parsons Green in west London, injuring 30 people. Two hours afterwards, the Metropolitan Police said they were investigating a terrorist incident.
On Friday evening, the Islamic State claimed the attack, saying it had been carried out by their 'soldiers', although the group has made false claims in the past.
Theresa May raised the UK's threat level to critical on Friday night and soldiers were deployed to guard key sites, such as nuclear power stations, to free up armed police for regular patrols.
These are the updates since then -
- Parsons Green underground station reopened on Saturday morning following the attack at 8.20am on Friday;
- 18-year-old 'suspected bomber' was arrested in Dover at 7.50am and at 2pm police stormed house in Sudbury;
- Unconfirmed reports from locals said police found explosives in the garden of the terraced house;
- Suspect was arrested two weeks ago, neighbours claimed, although Scotland Yard declined to comment;
- The Metropolitan Police said officers 'open minded' about whether more than one person was responsible;
- Police have received 180 photos and videos, located 121 witnesses and have spoken to 100 of them already;
- Public have been told to dial 999 or call the anti-terror hotline on 0800 789 321 if see anything suspicious.
Home Secretary Amber Rudd described arrest of the 18-year-old at 7.50am in the Dover port departure lounge as 'very significant', but added: 'The operation is ongoing.'
The suspect was taken to a local police station and will be transferred to south London during the course of the day, officers said.
One witness said the man was arrested in the ticket office at the port.
She told The Sunday Mirror: 'He was surrounded by about seven police officers as he went to buy a ticket. It was all done very quickly and quietly.
'I couldn't really see who he was or what he was wearing as they were all around him. 'I didn't realise what it was at the time. It's only after and heard it on the news I realised what it was.'
Tourist Daniel Vaselicu, 31, said the man appeared calm as the officers two unarmed interrogated him for 10 minutes before arresting him minutes later.
Police were seen searching bins outside Dover Priory railway station on prompting suggestions the suspect may have arrived in the town by train.
The station also has CCTV cameras positioned in and outside the building. The station is a 30 minute walk to the port. Police officers also searched industrial bins at the Dover ferry passenger terminal.
Officers were pictured lifting plastic carrier bags out of the bin and examining them before putting them back.
Security minister Ben Wallace said today the threat level has been raised to critical because a new attack is likely to be 'imminent' as an increased presence of armed officers was seen in cities across the country.
But he piled the pressure on police for not releasing CCTV footage of the attacker, describing it as a 'useful' tool in identifying suspects.
He said on BBC Radio 4's Today show this morning: 'I totally agree that CCTV footage is useful but that part of the investigation I leave with the police and security services.'
It was the middle of rush hour on Friday when the crude bucket bomb - which had a timer - went off at 8.20am inside a tube train packed with commuters, including schoolchildren and a pregnant woman.
The train is regularly packed full of schoolchildren. The Fulham area serves at least three state secondary schools: Fulham Boys School, The London Oratory and Lady Margaret Hall along with a number of independent schools.
Terrified passengers were left covered in blood with scorched hands, legs, faces and hair – others suffered crush injuries during a stampede as they 'ran for their lives' over fears the 'train would blow up'.
London Ambulance took 19 patients to hospitals, while the others went in themselves. The four hospitals dealing with patients were Imperial, Chelsea and Westminster, Guy's and St Thomas' and St George's.
An officer at the scene on Friday told MailOnline: 'We believe there is a second bomb - there is a man with knives on the loose.'
In a pre-recorded television statement released around 8.30pm, Mrs May said military personnel would replace police officers 'on guard duties at certain protected sites which are not accessible to the public'.
She said: 'The public will see more armed police on the transport network and on our streets, providing extra protection.
'This is a proportionate and sensible step which will provide extra reassurance and protection while the investigation progresses.'
Speaking moments afterwards, Assistant Commissioner Mike Rowley said: 'We are making excellent progress at the moment as we pursue our lines of inquiry to identify, locate and arrest those responsible.
'We have hundreds of police officers trawling through CCTV footage, detectives have spoken to tens of witnesses and we have taken a large number of calls to the hotline... from members of the public.
Donald Trump tweeted just hours after the blast that police had the attacker 'in their sights' and should have been 'more proactive' in catching 'the loser'.
Scotland Yard hit back and said Mr Trump's comments were 'pure speculation' while senior officers refused to name the suspect.
The President later adopted a more conciliatory tone in another tweet last night saying, 'our hearts and prayers go out to the people of London'.
Mrs May also hit out at the President's tweet, calling it 'unhelpful', and has this evening discussed the intelligence sharing between the two countries with the President in a telephone call.
Turns out, Trump was right.