Police have traced three of the four bombers back to West Yorkshire.
They were first alerted when the mother of Hasib Hussain, 18, rang the casualty line to report him missing after the blasts. He had told his family he was going on a day trip to London and had not been heard of since.
Officers found his property on the bombed bus at Tavistock Square and began to link him with three other men at the other bomb locations.
On Tuesday 12 July, police carried out raids on six houses in Leeds and Dewsbury.
They searched Hussain’s family home on Colenso Mount in the Holbeck area. In neighbouring Beeston they also raided the Colwyn Road home of his friend Shehzad Tanweer, 22, and a further unoccupied house on Stratford Street.
Meanwhile, officers sealed off an area around Alexandra Grove in the Burley area of Leeds and evacuated about 500 people.
And in Dewsbury they raided addresses at Thornhill Park Avenue and Lees Holm, belonging to Mohammed Sadique Khan and members of his family.
Forensic experts have combed a house in Aylesbury in Buckinghamshire on Wednesday night. Sources have since indicated the fourth bomber was almost certainly Jamaican-born Lindsey Germaine.
On Thursday, Head of Scotland Yard’s anti-terrorist Branch Peter Clarke appealed for information about Hussain – exhibiting CCTV footage and a photograph in the hope of persuading the public to come forward.
The suspected bombers appear to have led quiet lives.
Shehzad Tanweer, 22, lived in the Beeston area of Leeds. He was a sports science graduate who loved cricket and occasionally worked in his father’s fish and chip shop.
He was good friends with Hasib Hussain, 18, who lived nearby in the Holbeck district of the city. Neighbours said he was a quiet boy who had become religious a couple of years ago.
Mohammad Sidique Khan, the third bombing suspect, lived in Dewsbury, a few miles south of Leeds. He is believed to have been married with an eight-month-old daughter.
It appears that on the morning of the bombings, the three drove to Luton in a hire car where they met the fourth man.
Leaving the car in the station carpark, all four boarded a Thameslink train to London King’s Cross.
Once there, they fanned out across the Tube network. Khan and Tanweer took the Circle line in opposite directions while the unnamed man took the Piccadilly line south. Bombs went off on those three lines at 0850.
Hussain may have tried to board the Northern line but it was suspended. He ended up on a No. 30 bus which exploded at 0947 in Tavistock Square.
Police sources are indicating the fourth suicide bomber was a Jamaican-born British resident named Lindsey Germaine.
Little is known of his background and sources say confirmation of his identity may depend on DNA analysis.
