A teenage terror suspect was a spiky-haired and pierced techno music fan before he changed his image, dressed in robes and grew a beard.

The 19-year-old, named locally as Andrew Ibrahim, is being held by police under the Terrorism Act 2000 and was arrested on Thursday after a tip-off.

Three controlled explosions have been carried out at his home, in the Westbury-on-Trym area of Bristol, after a search uncovered a "suspicious substance".

Police carried out one explosion shortly after the arrest, and two further detonations on Saturday.

A picture of Ibrahim on the social networking website MySpace shows him with dyed red hair and facial piercings. His profile also lists his favourite music as hardcore, trance and techno.

He describes himself as a non-smoking teetotal Muslim, but has not visited his page since 2006.

A source, who says he worked with the teenager said Ibrahim's appearance has changed dramatically since the picture was taken.

Avon and Somerset Police have been granted seven days to question Ibrahim, who lived alone at the 1950s red-brick terrace property in a cul-de-sac and had recently started a course at the University of the West of England. His father is reported to be Nassif Ibrahim, an NHS pathology consultant at Frenchay hospital, Bristol.

The source said he had endured a “difficult few years” and had been “unsettled”.

“He was struggling in life but I had no idea he had become a Muslim before I saw him two weeks ago,” the man said.

“I could not believe my eyes. He was dressed in full robes and had a beard. He must have undergone a massive change in identity.”

Neighbours described Ibrahim, who they said had not been in the house long, as heavily built and often seen wearing traditional Muslim dress and carrying a satchel.

Others said they had confronted him about “loud chanting” a few days ago. Police have not ruled out further arrests.

Jackie Roberts, assistant chief constable at Avon and Somerset Police, said: “This is a genuine incident which we are taking extremely seriously.”

Ibrahim was not arrested at the house, but elsewhere in Bristol, and lived alone, Roberts said.

“Obviously we are in the early stages of this investigation, extensive inquiries are ongoing and obviously things will unfold as the days go by.”

Between 40 and 50 neighbours in the cul-de-sac where the 1950s red-brick terrace is cordoned off were evacuated before the explosion.

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