A baby-faced poker fanatic was last night at the centre of a major counter-terror investigation into a crude bomb left on a Tube train.
The investigation took a dramatic turn when officers in Newton Abbot, Devon, raided the former home of Damon Smith, 19, and found a suspicious device.
He was later named as the suspect being questioned by police investigating the device found in London last week.
Devon police called in Scotland Yard, which sent in officers by helicopter and evacuated locals amid fears of an explosion. Roads were closed, football matches cancelled to allow helicopters to land and drinkers told they could not leave a local pub.
But experts ruled that the item discovered in the house was not a viable explosive device.
Friends said Smith was interested in Islam and the Syria conflict, and had recently begun reading the Koran. He also appears to have travelled to Turkey and Tunisia on holiday earlier this year.
Relatives said they "would not talk about it" when asked about Smith's arrest yesterday. His mother Antonitza, 47, was in hiding in nearby Torquay.
Smith had moved out of the house in Devon and relocated to London several months ago with his mother, who requested a council house transfer.
The operation was part of a fast-moving investigation that began on Thursday when an explosive device was found on a Jubilee line Tube train. Bomb disposal experts conducted a controlled explosion after a 'bag of wires' was found in a carriage that had just passed under Canary Wharf and Westminster.
Security sources said the device was "viable" but at the 'bottom end of seriousness'.
Thousands of officers were put on standby as a manhunt was launched. Smith was arrested in the street in north London on Friday lunchtime by undercover armed officers.
He was Tasered and wrestled to the ground a short distance from Holloway Road Tube station, about nine miles from North Greenwich station where the package was found. Last night he remained in custody and is being questioned on suspicion of preparing terrorist acts.
Residents living near his former home in Newton Abbot, a £100,000 (NZ$170,473) modern terrace close to the local police station, said he had lived there for around five years but moved to London over the summer to attend university and was joined by his mother, who feared he would struggle to cope on his own.
They said he was a keen judo fighter, who had competed for a local club, and a fanatical poker player who regularly travelled to a casino in Plymouth. In photographs on his Twitter account, Smith poses with wads of cash he had won.
Other online posts suggest Smith has an interest in guns and the Irish republican cause.
One poker opponent, who played against Smith up to ten times, said he always arrived with his mother and stood out because of his distinctive "squeaky voice".
"He is quite young-looking and always wears a hat," he said. "He had a very feminine voice. His mum and him stood out.
"The main thing was his voice. It was squeaky. He sounded like a ten-year-old girl.
"He did not drink alcohol. He was a decent player but he never had much money."
A mother of another judo fighter at the club Smith fought at said he had been banned from the club for punching her son in the face following a fight.
She added: "He was always with his mum. He was a mummy's boy but he didn't appreciate it."
One former neighbour, 81, said: "He seemed like a normal teenager. You used to see him walking the dog."
A Metropolitan Police spokesman said they are not looking for anyone else in connection with their inquiry.
Officers were granted a warrant of further detention on Saturday night and can hold him for up to 14 days.