To his fellow students visiting the tourist spots of London, Umar Farouk Abdulmutallab was known affectionately as 'the Pope'.
It was a nickname the popular teenage son of a millionaire Nigerian banker had earned because he did so little wrong.
Fellow student Efemena Mokedi said: 'He was very popular, a good guy, a very religious person, a very honest person who was friends with all the teachers.'
Pictured: Bomber Umar Farouk Abdulmutallab, in the red jacket, outside Buckingham Palace
He was to return in 2005, when he began a three-year course in engineering at University College. According to reports last night, his family fear this was when his radicalisation began.
One friend said: 'When his degree course ended, he "disappeared" to Yemen, where he was being taught Arabic. His family are suggesting he was probably recruited in London but became radicalised in Yemen. He had been in Yemen for about a year or even a year and a half.'
Abdulmutallab is said to have told U.S. investigators he had been trained in terror techniques by Al Qaeda after travelling to Yemen and then sent on the mission to bring carnage to the skies over the U.S.
Trafalgar trip: Again in the red jacket, Umar Farouk Abdulmutallab outside another London landmark
'We are looking at a very unusual recruit ... a man who has been persuaded to reject his family, his heritage and his background,' a U.S. investigator said. 'We need to find out why and how very quickly.'
The arrest has stunned British history teacher Michael Rimmer, who taught Abdulmutallab in Togo. He said the student had been 'every teacher's dream - very keen, enthusiastic, very bright, very polite'.
Abdulmutallab with the woman believed to be his mother
Abdulmutallab's family home in Nigeria
He said Abdulmutallab had been among a number of pupils he had taken to London in 2001 and 2002, when aged 13 and 14.
At one stage on the trip, Abdulmutallab had become upset because several older students had visited a pub and he thought it should not have been allowed on religious grounds.
Mr Rimmer said that rather than spend money on souvenirs in London, Abdulmutallab had donated £50 to an orphanage.
'At one stage, his nickname was "the Pope". In one way, it's totally unsuitable because he's a Muslim, but he did have this saintly aura. He was a model student, very keen, enthusiastic and loved the subject I taught him, history, and would often stay behind after lessons to discuss items in the lesson or in the news.'
Pictured: Posing in Parliament Square alongside peace protester Brian Haw
'I remember in 2001 there was a class discussion about the Taliban in Afghanistan. All the other children including all the Muslims thought they were a bunch of nutters with beards, but he thought they had it right and thought their views were acceptable. At the time I thought, well, young people have silly views and he would grow out of it.
'I was angry at the nutters who had put these silly ideas in his head but also angry with him because he had wonderful parents and comes from a lovely family, with lots of friends and had everything going for him.
'He's a fine looking lad, very bright and I expected great things of him. But he's thrown it all away and his parents will be devastated.'
Abdulmutallab had told Mr Rimmer that he was going to study Arabic in the Yemen.
'I thought nothing of it at the time. I just thought he was being adventurous, instead of going to more mainstream places like Damascus.'
Police search a property in central London, now sealed off to the public
Mr Mutallab, an influential banker who is well connected in Nigerian politics, approached the U.S. embassy in Abuja to express concerns that his son had been radicalised.
US officials said Abdulmutallab had been added to a broad terrorism watchlist, but was not flagged for mandatory secondary screening or put on a no-fly list.
Mr Mutallab flew yesterday from the family home in Funtua in Nigeria's northern Katsina State to meet security agencies and discuss the activities of his son, the youngest of his 16 children.
'I have been receiving telephone calls from all over the world about my child who has been arrested for an alleged attempt to bomb a plane,' he said yesterday.
'I am really disturbed. I would not want to say anything at the moment until I put myself together...I have been summonedby the Nigerian security and I am on my way to answer the call.'
Mr Mutallab, who retired last week after heading both his country's major banks, said he was surprised that despite his expressing his concerns, his son's name had not been placed on a no-fly list.
A close neighbour in Funtua said he believed Abdulmutallab did not get his extremist ideas from his family or from within Nigeria.
'I believe he must have been lured where he is schooling to carry out this attack,' said Basiru Sani Hamza, 35. 'Really, the boy has betrayed his father, who took care of all his needs.'
While in London, where he graduated with a 2.2 in mechanical engineering and business finance, Abdulmutallab lived in a three-bedroom apartment in the West End paid for by his father.
Other members of the family also occupied the flat close to Oxford Circus and Harley Street from time to time. It is part of an imposing, sevenstorey block in Mansfield Street which has an English Heritage blue plaque on a wall in honour of the philanthropist Sir Robert Mayer, who once lived there.
One woman, who works as a carer for an elderly female resident, said Abdulmutallab's family were not always there. 'They only come when it is school holidays, they don't really stay there. Most of the people in these apartments have got houses in the country, so most of them are empty.'
Police yesterday continued to carry out searches at the flat which, records show, is owned by a U.S. investment company. Scotland Yard confirmed that it was liaising with the U.S. authorities investigating the failed attack. Officers also visited UCL.
It was in June 2008, shortly before he completed his course at UCL, that Abdulmutallab successfully applied for a twoyear visa to the U.S., valid until June 12, 2010.
