Curiously all four men's documents were found at the bomb sites. Khan's documents were found at three of the sites. The discoveries helped police quickly identify the men which led to further incriminating evidence and information being found and revealed. Suicide bombers usually strip themselves of ID.
See government references to identification in the reports analysis
Times: Police had no need of DNA evidence to identify the bombers as the men were all carrying personal documents.
Times: Documents from one of the group were found on both the bombed-out train at Aldgate and the one at Edgware Road. Police will not say why.
All four men's Documents at bomb sites
Deputy Assistant Commissioner Peter Clarke: Reports documents found at bomb sites - wmv
Boston Herald: 'They wanted to be known': Suicide bombers had IDs
Independent: The reconstruction: 7/7 - What really happened?