The alleged “refugee” teenager held in connection with Friday’s terror attack in London was arrested just two weeks before the attack, neighbours who knew his foster family have claimed.

The “foreign” 18-year-old is thought to have been living with a well-known foster couple in Sunbury-on-Thames.

Police raided the address on Saturday in connection with an attack Friday morning on London’s Tube network. A ‘bucket bomb’ with a timer partially detonated at Parson’s Green station injuring around 30 people. Islamic State has claimed responsibility.

Serena Barber, 47, who has known the foster couple, Penelope Jones, 71, and her husband Ronald, 89, all her life and lives in a property backing onto theirs, told the Daily Mail:

“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 Joneses were both honoured by the Queen in 2009 and had reportedly come out of retirement in response to the migrant crisis.

The claim comes after U.S. President Donald Trump claimed on Twitter the terrorists responsible for the attack has been “in the sights on of Scotland Yard”.

Another attack in London by a loser terrorist.These are sick and demented people who were in the sights of Scotland Yard. Must be proactive! — Donald J. Trump (@realDonaldTrump) September 15, 2017

The couple has fostered 268 children, including refugees and migrants from Syria. They featured in an interview with Elmbridge CAN, a community group which aims “to build a culture of welcome to refugees”. The website has recently been taken down.

The teenage suspect was arrested early on Saturday morning in the departure lounge at Dover port and could have been attempting to escape the country.

Metropolitan Police Deputy Assistant Commissioner Neil Basu said on Saturday: “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 11 am 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,” Basu also confirmed in relation to the Surrey raid.

“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.”

Metropolitan Police confirmed Sunday that a second arrest in connection to the terrorist attack was made late Saturday night.