A police forensics officer leaves a house in Leeds in northern England after raids in connection with the London bombings.
British police raid several residences in northern England as part of the investigation into last week's bombings in London. Investigators are suggesting that the four bombs that exploded last Thursday were of military quality and technically advanced — not the crude devices that were initially suspected.
Britain's prime minister, Tony Blair, is promising an investigation "among the most vigorous and intense the country has ever seen." Police say that close circuit television tapes may help investigators.