Photos have emerged of one of the terror suspects arrested over the attempted bombing on a London Underground train.

Yahyah Farroukh is one of two refugees who were fostered by the same couple being questioned by police on suspicion of terror offences.

The 21-year-old was arrested outside the fastfood shop where he worked in Hounslow on Saturday night, hours after the chief suspect was detained in Dover.

Farroukh's Facebook page says he comes from the Syrian capital of Damascus and includes posts documenting his journey to Europe via Egypt and a refugee boat across the Mediterranean in 2013.

More recent photos show him partying, shopping and out with friends, with posts on Instagram suggesting he smoked cannabis and took drugs.

Last month, he posted emotional messages and photos of his father, who is thought to have died recently in Egypt.

Farroukh's page says he has worked for nightclub promoters in London and studied English at West Thames College. He is thought to have a cousin who lives in Scotland with his children.

Police have not confirmed details of his alleged links to the Parsons Green attack but former colleagues told The Independent they had "not even an inkling" of suspicious behaviour.

Armed police search home linked to teenage Parsons Green Tube bombing suspect in Surrey

“He didn’t look outwardly religious at all,” said Suleman Sarwar, who runs Aladdin's Fried Chicken.

“He dressed like any other twenty-something: jeans, T-shirt, no distinct beard. Very, very, very normal.”

Farroukh had prayed regularly alongside other staff and customers at the restaurant’s upstairs prayer room but showed no signs of extremism, he added.

The main suspect, an 18-year-old man, was arrested on Saturday morning in Dover, where he was reportedly attempting to buy a ferry ticket to Calais.

Suspect pictured with Lidl bag around 7am on the morning of the attack (PA)

Police said they could not give any further details on his identity due to "strong investigative reasons" but local officials identified him as an Iraqi refugee.

Farroukh and the teenager, who has not yet been identified, are believed to have been taken in at different times by a British couple known for their dedication to fostering.

Penelope and Ronald Jones, aged 71 and 88 respectively, were made MBEs for services to children and families in 2009 and have fostered hundreds of children.

Their home in Sunbury-on-Thames remains cordoned off after a raid by armed police, who evacuated nearby homes as a precaution on Saturday.

Yahyah Farroukh, 21, the second suspect arrested in relation to the Parsons Green attack (Facebook)

Neighbours told The Independent explosives and weapons had been found at the property, but investigators have not confirmed the result of searches.

Assistant Commissioner Mark Rowley, the national lead officer for counter-terror policing, said there had been “rapid progress” in the investigation.

“There are now two searches continuing at addresses in Surrey and we are getting a greater understanding of the preparation of the device,” he added.

It came after 30 people were injured when a “fireball” ripped through a train at Parsons Green station in the height of morning rush hour.

Officials said the blast was caused by the partial detonation of a failed bomb, which experts said could have killed everyone in the carriage.

Isis claimed responsibility for the attempted massacre, which it claimed was carried out by “soldiers of the caliphate”.

Less than two hours before the explosion, a young man was caught on CCTV leaving the Jones’ home carrying a Lidl bag similar to that containing the device.

Footage shows the man, wearing a red hat and grey tracksuit, walking swiftly down the road with his head down.

Ian Harvey, a local politician, said he understood an 18-year-old Iraqi orphan was living with Mr and Mrs Jones, having moved to Britain aged 15 after his parents died.

Their neighbour Serena Barber, 47, said the couple were currently caring for two foreign boys, describing one as polite but the 18-year-old as “awful”.

Terror attack at Parson's Green – in pictures Show all 23 1 /23 Terror attack at Parson's Green – in pictures Terror attack at Parson's Green – in pictures Parsons Green explosion A bucket with flames and wires coming out of it was photographed in the carriage after the explosion – apparently the source of the blast AFP Terror attack at Parson's Green – in pictures Parsons Green explosion An explosion on a packed Tube train has injured a number of people in west London AFP/Getty Terror attack at Parson's Green – in pictures Parsons Green explosion The blast triggered a stampede as commuters panicked AFP/Getty Terror attack at Parson's Green – in pictures Parsons Green explosion Click through for more pictures from the scene Reuters Terror attack at Parson's Green – in pictures Parsons Green explosioN A police officer and a sniffer dog stand in the street near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs Reuters Terror attack at Parson's Green – in pictures Parsons Green explosion Handout photo issued by James Treen of emergency services attending an incident at Parsons Green station in west London amid reports of an explosion. PRESS ASSOCIATION Photo. Issue date: Friday September 15, 2017. See PA story TRANSPORT Explosion. Photo credit should read: James Treen/PA Wire NOTE TO EDITORS: This handout photo may only be used in for editorial reporting purposes for the contemporaneous illustration of events, things or the people in the image or facts mentioned in the caption. Reuse of the picture may require further permission from the copyright holder. PA Terror attack at Parson's Green – in pictures Parsons Green explosion Police vehicles line the street near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs Reuters Terror attack at Parson's Green – in pictures Parsons Green explosion A police officer stands outside Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs Reuters Terror attack at Parson's Green – in pictures Parsons Green explosion Armed British police officers stand on duty outside Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. Police and ambulance services said they were responding to an "incident" at Parsons Green underground station in west London on Friday, following media reports of an explosion. A Metro.co.uk reporter at the scene was quoted by the paper as saying that a white container exploded on the train and passengers had suffered facial burns. / AFP PHOTO / Daniel LEAL-OLIVAS / ===RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / HO / @RRIGS - NO MARKETING NO ADVERTISING CAMPAIGNS NO ARCHIVES - DISTRIBUTED AS A SERVICE TO CLIENTS FROM FROM ALTERNATIVE SOURCES, THEREFORE AFP IS NOT RESPONSIBLE FOR ANY DIGITAL ALTERATIONS TO THE PICTURE'S EDITORIAL CONTENT, DATE AND LOCATION WHICH CANNOT BE INDEPENDENTLY VERIFIED == / DANIEL LEAL-OLIVAS/AFP/Getty Images AFP/Getty Terror attack at Parson's Green – in pictures Parsons Green explosion Emergency services attend the scene following a blast on an underground train at Parsons Green tube station in West London, Britain September 15, 2017, in this image taken from social media. TWITTER / @ASolopovas/via REUTERS THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. NO RESALES. NO ARCHIVES. MANDATORY CREDIT Reuters Terror attack at Parson's Green – in pictures Parsons Green explosion Armed British police officers stand on duty outside Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. Police and ambulance services said they were responding to an "incident" at Parsons Green underground station in west London on Friday, following media reports of an explosion. A Metro.co.uk reporter at the scene was quoted by the paper as saying that a white container exploded on the train and passengers had suffered facial burns. / AFP PHOTO / Daniel LEAL-OLIVAS / ===RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / HO / @RRIGS - NO MARKETING NO ADVERTISING CAMPAIGNS NO ARCHIVES - DISTRIBUTED AS A SERVICE TO CLIENTS FROM FROM ALTERNATIVE SOURCES, THEREFORE AFP IS NOT RESPONSIBLE FOR ANY DIGITAL ALTERATIONS TO THE PICTURE'S EDITORIAL CONTENT, DATE AND LOCATION WHICH CANNOT BE INDEPENDENTLY VERIFIED == / DANIEL LEAL-OLIVAS/AFP/Getty Images AFP/Getty Terror attack at Parson's Green – in pictures Parsons Green explosion Armed British police officers stand on duty outside Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. Police and ambulance services said they were responding to an "incident" at Parsons Green underground station in west London on Friday, following media reports of an explosion. A Metro.co.uk reporter at the scene was quoted by the paper as saying that a white container exploded on the train and passengers had suffered facial burns. / AFP PHOTO / Daniel LEAL-OLIVAS / ===RESTRICTED TO EDITORIAL USE - MANDATORY CREDIT "AFP PHOTO / HO / @RRIGS - NO MARKETING NO ADVERTISING CAMPAIGNS NO ARCHIVES - DISTRIBUTED AS A SERVICE TO CLIENTS FROM FROM ALTERNATIVE SOURCES, THEREFORE AFP IS NOT RESPONSIBLE FOR ANY DIGITAL ALTERATIONS TO THE PICTURE'S EDITORIAL CONTENT, DATE AND LOCATION WHICH CANNOT BE INDEPENDENTLY VERIFIED == / DANIEL LEAL-OLIVAS/AFP/Getty Images AFP/Getty Terror attack at Parson's Green – in pictures Parsons Green explosion Armed policemen stand by cordon near Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Hannah McKay Reuters Terror attack at Parson's Green – in pictures Parsons Green explosion A woman reacts outside Parsons Green tube station in London, Britain September 15, 2017. REUTERS/Kevin Coombs Reuters Terror attack at Parson's Green – in pictures LONDON, ENGLAND - SEPTEMBER 15: Emergency services outside of Parsons Green Underground Station on September 15, 2017 in London, England. Several people have been injured after an explosion on a tube train in south-west London. The Police are treating the incident as terrorism. (Photo by Jack Taylor/Getty Images) Getty Terror attack at Parson's Green – in pictures LONDON, ENGLAND - SEPTEMBER 15: A fireman walks past the police cordon at Parsons Green Underground Station on September 15, 2017 in London, England. Several people have been injured after an explosion on a tube train in south-west London. The Police are treating the incident as terrorism. (Photo by Jack Taylor/Getty Images) Getty Terror attack at Parson's Green – in pictures LONDON, ENGLAND - SEPTEMBER 15: A tube train is seen stopped at Parsons Green Underground Station on September 15, 2017 in London, England. Several people have been injured after an explosion on a tube train in south-west London. The Police are treating the incident as terrorism. (Photo by Chris J Ratcliffe/Getty Images) Getty Terror attack at Parson's Green – in pictures LONDON, ENGLAND - SEPTEMBER 15: Police officers stand by a cordon at Parsons Green Underground Station on September 15, 2017 in London, England. Several people have been injured after an explosion on a tube train in south-west London. The Police are treating the incident as terrorism. (Photo by Jack Taylor/Getty Images) Getty Terror attack at Parson's Green – in pictures Police forensics officers works alongside an underground tube train at a platform at Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. Police and ambulance services said they were responding to an "incident" at Parsons Green underground station in west London on Friday, following media reports of an explosion. "We are aware of an incident at Parsons Green tube station. Officers are in attendance," London's Metropolitan Police said on Twitter. / AFP PHOTO / Daniel LEAL-OLIVAS / (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images) AFP/Getty Terror attack at Parson's Green – in pictures LONDON, ENGLAND - SEPTEMBER 15: Emergency serivces attend to the scene near Parsons Green Underground Station on September 15, 2017 in London, England. Several people have been injured after an explosion on a tube train in south-west London. The Police are treating the incident as terrorism. (Photo by Jack Taylor/Getty Images) Getty Terror attack at Parson's Green – in pictures Members of the emergency services work outside Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. British police are treating an incident on a London Underground train on Friday as an act of terrorism, saying "a number of people" had been injured. "Terrorist incident declared at Parsons Green Underground Station," police said in a statement. / AFP PHOTO / Daniel LEAL-OLIVAS (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images) AFP/Getty Terror attack at Parson's Green – in pictures Armed British police officers walk through the carriage of a London underground tube carriage at Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. Police and ambulance services said they were responding to an "incident" at Parsons Green underground station in west London on Friday, following media reports of an explosion. A Metro.co.uk reporter at the scene was quoted by the paper as saying that a white container exploded on the train and passengers had suffered facial burns. / AFP PHOTO / Daniel LEAL-OLIVAS (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images) AFP/Getty Terror attack at Parson's Green – in pictures Members of the emergency services and armed police officers work alongside an underground tube train at a platform at Parsons Green underground tube station in west London on September 15, 2017, following an incident on an underground tube carriage at the station. Police and ambulance services said they were responding to an "incident" at Parsons Green underground station in west London on Friday, following media reports of an explosion. "We are aware of an incident at Parsons Green tube station. Officers are in attendance," London's Metropolitan Police said on Twitter. / AFP PHOTO / Daniel LEAL-OLIVAS (Photo credit should read DANIEL LEAL-OLIVAS/AFP/Getty Images) AFP/Getty

“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,” she told the Daily Mail.

“After that Penny said she was going to have to stop caring for him, she couldn't handle him.”

According to a couple, who asked not to be named, one of the young men cared for by the couple stayed up late at night and was often visited by two male companions, who appeared to be in their late teens.

Farroukh is believed to have left their care earlier this year and has been living at a home in Stanwell, which was also searched by police.

Footage showed him being detained outside Aladdin's where a witness said four undercover counter-terror police officers tackled him to the ground.

“The guy was screaming,” the witness told The Sun. "When they took him down his phone went flying and he dropped his bag containing a drink can and a KitKat.

“The cops were shouting to get his phone. I guess because it holds important information.”

Farroukh was restrained, put in overalls and driven away. He and the 18-year-old remain in custody as they are questioned on suspicion of terror offences.

Officials have lowered the national terror threat level from “critical” to “severe”, indicating that police are not urgently seeking anyone else in relation to the attack.