A British newspaper says Britain's domestic intelligence agency, MI-5, investigated one of the suspected London suicide bombers last year, but determined he was not a threat. The Sunday Times reports that MI-5 had checked out Mohammad Sidique Khan, but did not put him under surveillance. British officials had no comment. A photograph showing the four suspected bombers entering a rail station the morning of the attacks appeared in Sunday papers. Bombers attacked three London subway trains and a double-decker bus two weeks ago, killing more than 50 people. Meanwhile, British police arrested six men Sunday near the central city of Leeds, where at least two of the bombing suspects lived. The six were picked up under Britain's anti-terrorism laws. Police say there is no link at this time to the London attacks.