Police searched the home of a second refugee foster child last night as part of the terror investigation into the Parsons Green bombing in the UK.
A 21-year-old man was arrested in Hounslow on Saturday night just hours after police caught the 18-year-old suspected of planting the Tube bomb at the Port of Dover.
After the second arrest officers cordoned off a property just yards from Heathrow Airport linked to a Syrian refugee who had previously lived at the home of Ron and Penny Jones, who had been fostering the 18-year-old before his arrest.
Yahyah Farroukh, believed to be in his early 20s, was registered at living in the property in Stanwell, Surrey, and had previously been listed at the Joneses house in Sunbury on Thames.
According to his Facebook page Farroukh had moved to the UK from Damascus.
Friends of the Joneses said the elderly couple, who had taken in hundreds of children since the 1970s, had only recently returned to fostering after being moved by the plight of youngsters caught up in the refugee crisis.
Family friend, Jim Adaway, 37, said the couple had wanted to help resettle children from overseas, particularly war zones, but had been struggling to cope with one of the children in their care.
Mr and Mrs Jones, who were appointed MBEs for their fostering work in 2009, described how they felt compelled to help others and had kept in touch with many of the young people who had shared their home.
Mrs Jones said the children she took in needed to be loved and made to feel special.
She said: "We open our hearts to all the children. Anybody that comes to us we will do whatever we can do to help them with whatever they need."
She added: "There must have been hundreds of children. I try to stay in touch with them. Some have been adopted. I send them birthday cards - it's a very extended family."
The couple, who had six children between them, were being looked after by relatives as police continued to scour their home for clues.
Neighbours of the Stanwell property which was cordoned of by police said that Mr Farroukh had moved into the property more than a year ago .
One said: "There would be men going in his house. There's always cars coming and going. They all talk Arabic.
"Some of them wear caps on their heads and the long (traditional) dress. He didn't dress in traditional dress.
"When he walks around he's always on his mobile. He speaks Arabic.
"Sometimes I've seen him with a black thing around his head."
Pat Hodge, who works in a warehouse, said: "I thought he was a student. He would always wave to us, the others wouldn't.
"They would set out prayer mats in the garden. They always had something, like gadgets, in their hand but there was no TV, no furniture in the house."
A Metropolitan Police spokesman said: "Three addresses are now being searched; two searches are continuing at addresses in Surrey and a further search is taking place in Hounslow in connection with the ongoing investigation into the Parsons Green incident."
Speaking about the second arrest, a Metropolitan Police spokesman said: "A second man has been arrested by detectives from the Met's Counter Terrorism Command investigating the terrorist attack at Parsons Green on Friday, 15 September.
"The 21-year-old man was arrested in Hounslow at around 23:50hrs on Saturday, 16 September.
"He was arrested under section 41 of the Terrorism Act and taken to a south London police station where he remains in custody."