Police raids gave first results after the search started for those who could have been involved in organization and implementation of the terrorist attacks in London.
Police arrested a man in a northern Muslim neighborhood as they examined whether four suspects - possibly suicide bombers - died in the attacks, reports the AP.
At least three of the suspected bombers came from the West Yorkshire region, which includes Leeds, said Peter Clarke, head of the Metropolitan Police anti-terrorist branch.
Closed-circuit TV video showed that all four had arrived at King's Cross station by 8:30 a.m. on Thursday, about 20 minutes before the blasts began that killed at least 52 people, Clarke said.
In a Scotland Yard news conference, Clarke said police had "strong forensic and other evidence" that the man believed to have carried a bomb onto the subway train that exploded between the Aldgate and Liverpool Street stations died in the blast, and they were awaiting confirmation from the coroner. Police were trying to determine whether the other three also died in the explosions.
Police, who had been saying there was no evidence of suicide bombings, indicated that there had been a breakthrough in their inquiry.
"The investigation of what has been found will be a detailed and lengthy exercise," Clarke said, according to The Financial Times which published the full text of the statement by Peter Clarke on developments following the bombings in London on Thursday July 7.