Three young men from West Yorkshire were killed in last Thursday's bomb blasts in London.
Police cordoned off several streets in Leeds on Tuesday
Initially they would have been treated as victims. Now, they are suspected perpetrators of the UK's first suicide bomb attack.
Personal details suggest they lived typically low-key, suburban, "ordinary" lives.
Shehzad Tanweer, 22, was born in Bradford but lived most of his life in the Beeston area of Leeds.
He was a sports science graduate whose interests included cricket and ju-jitsu.
In 2004, he was arrested for disorderly conduct and cautioned.
Newspapers quoted friends who said that Mr Tanweer was quiet and very religious but did not express an interest in politics.
The Daily Mail reported he had been to an Islamic study camp in Pakistan at the start of the year.
His father, of Pakistani origin, owns a fish and chip shop near their home on Colwyn Road.
His uncle, Bashir Ahmed, 65, said the family was "shattered" by the revelation that he appeared to have been involved.
"He was proud to be British," he said. "He had everything to live for. His parents were loving and supportive.
"He was a very kind and calm person. He was respected by everyone."
Neighbours described the graduate, who studied at Leeds Metropolitan University, as a "good Muslim". Others said he was a "nice lad" who could "get on with anyone".
One friend said they played sport together only last week. "He's the type of guy who would condemn things like that," the friend said.
Yet, for all the tributes, it appears Shehzad Tanweer detonated a bomb on a Circle Line train between Aldgate and Liverpool Street stations which killed seven people, including himself, and injured over 100 more.
Living barely half a mile from Colwyn Road, teenager Hasib Hussain similarly had given friends and family little cause for concern.
The 18-year-old, reportedly a good friend of Shehzad Tanweer, is believed to have been a "tearaway" during his early teens before turning very religious about two years ago.
He had been on the Hajj, grew a beard and began to wear robes.
In 2004 he too was arrested and cautioned, for shoplifting.
Neighbours said he had lived all his life in Colonso Mount in the Holbeck area of Leeds. One neighbour described the family as "very nice people".
He said: "We all knew them but I
wouldn't say I knew them well. They were just a very nice family."
Hasib Hussain had told his family he was going on a trip to London to visit friends.
But when he failed to return on Thursday, his parents reported him as missing to police.
It appears he had in fact boarded the No 30 bus in London on Thursday armed with enough explosives to rip the double-decker apart, killing 13.
His driving licence and cash cards were found in the mangled wreckage of the bus.
Mohammad Sidique Khan, the third bombing suspect, lived in Dewsbury, a few miles south of Leeds.
He is believed to have been married with a very young daughter, with newspapers naming his wife as teacher Hasina Khan.
The 30-year-old had lived in Beeston but moved to Lees Holm in Dewsbury about
five months ago.
Mr Khan is believed to have been a "learning mentor" at Hillside Primary School in Leeds, dealing mainly with special needs children.
Parent Sharon Stevens, speaking outside Hillside, said others bringing their children to school could not believe what had happened.
"Everybody's shocked, totally shocked.
"He was really understanding and he did work for the children and parents. He was a big supporter of children and parents."
Another parent, Martina Preissnerova, said she was considering leaving Leeds, admitting: "I am scared a little bit."
She said her son had pointed out Mr Khan's picture in a newspaper.
Shehzad Tanweer was born in Bradford and brought up in Leeds
One neighbour said she had seen Mr and Mrs Khan just a few days before the bombings. "They seemed a right quiet couple," she said.
Another neighbour said: "I never knew he had a religious background. I go to the local mosque and have never seen him there."
Documents belonging to Mohammad Sidique Khan were found in the debris of the Edgware Road blast, where seven people are so far confirmed dead.
Police are still searching for clues as to the identity of a fourth man, suspected of killing at least 21 people and injuring hundreds more on a Piccadilly Line train near King's Cross station.