Police who found the three boys who went missing four days ago said there may have been a plan to "spirit them out of the country."
They failed to return to their foster carers' home in Sunderland, after setting out on a tea-time bike ride to a local park.
Instead, they caught a Metro to Newcastle, then took a pre-booked taxi to London and spent two nights in the capital before heading for Birmingham.
Superintendent Alan Veitch, who led the major investigation to find them, said it was "entirely possible" that the plan was to get the boys out of the country.
Three boys from Sunderland who have been missing since Monday were found in the Lancashire area today, police said.
According to Northumbria Police, they had been to addresses in London, Birmingham and Lancashire while missing.
Officers say this appears to have been a carefully orchestrated pre planned operation and the boys will now be brought back to North East to be repatriated with their foster carers.
Police say seven arrests have been made in total in connection with their disappearance.
Three brothers who have been missing since Monday have been found safe and well, police have said.
Remus, Janko and David Matloch, aged 15, 12 and 10, sparked a manhunt after they failed to return to their foster parents' home in Sunderland after going on a tea-time bike ride.
CCTV showed the trio catching a Metro train to Newcastle but they were later found in the Lancashire area.
A Northumbria Police spokesman said: "All three boys have been found safe and well in the Lancashire area. The media and public are thanked for their assistance."
Police searching for three brothers missing since Monday have arrested a man and a woman in connection with their disappearance.
Remus, Janko and David Matloch, aged 15, 12 and 10, failed to return to their foster parents' home in Sunderland after going on tea-time bike ride.
Instead, they caught a Metro train to Newcastle and were last seen leaving Central station.
The boys have yet to be found but Northumbria Police said they arrested a 34-year-old man and a 39-year-old woman at an address in Birmingham last night.
Superintendent Alan Veitch, of Sunderland Area Command, said the investigation to find the brothers was still ongoing in both Birmingham and London.
A senior police officer said he was concerned for the safety of three young boys from Sunderland who are missing after apparently catching a Metro train to Newcastle.
They left their home together and did not return.
The case of three boys who went missing from their home in The Oaks area of Sunderland yesterday is not being treated as an abduction, Northumbria Police have said.
Border agencies and all UK police forces are on alert, they added.
Three boys missing in Sunderland had said they were going on a bike to Mowbray Park yesterday.
The boys were last seen in The Oaks area of Sunderland, Northumbria Police said.
Police searching for three missing brothers in Sunderland say the boys have not been answering their mobile phones and have not gone missing before.
Remus, Janko and David Matlock went for a bike ride on Monday evening to Mowbray Park, but did not return to their foster parents' home at The Oaks.
Remus, 15, is 5'7" tall, slim build, dark air in a big quiff at the front and shaved at the back. He was last seen wearing joggers, baseball cap and t-shirt and a black cycling helmet.
David, 10, is 4'8" tall, shaggy dark brown hair, chubby build, possibly wearing shorts and a top and a silver coloured cycling helmet.
Janko, 12, is 4'8" tall, fair hair styled in a quiff and short at the back, medium build. He was last seen wearing smart mustard coloured chinos, converse type trainers, blue lightweight waterproof jacket and a silver cycling helmet.
Three brothers have gone missing from their foster home in Sunderland.
They went out for a bike ride on Monday, but did not return. Police say Remus, Janko and David Matlock are Polish, but speak good English.
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