London (AsiaNews/Agencies) Scotland Yard is still hunting for those who placed four explosive devices on London transit that only partially detonated at 12:30 pm yesterday. Two men who looked like they might be of Asian descent and who were detained were released.
Investigators will be helped by the fact that the three devices on London Underground trains and the one on a bus did not fully go off.
"We do believe that this may represent a significant breakthrough in the sense that there is obviously forensic material at these scenes which may be very helpful to us," Metropolitan Police Commissioner Ian Blair said. "Clearly the intention must have been to kill. You don't do this with any other intention."
Yesterday's incidents unfolded very much like those of July 7. Explosive devices were placed on three trains near Warren Street, Oval and Shepherd's Bush stations, and one on a bus running east of the centre.
One man said he saw a young Asian male lying on the floor of a train carriage with a ripped rucksack with a puff of smoke coming out of it. The young man looked dazed and confused and very shaken, like someone who just got something wrong happen.
According to Magnus Ranstorp, director of the Centre for the Study of Terrorism and Political Violence at the University of Saint Andrews in Scotland said the bombs may have been a "bad batch" or badly wired.
The July 7 attack that killed 56 and injured 700 used a highly unstable explosive compound that degraded quickly and it might be same used yesterday.
For Michael Clarke, security expert at King's College London, the two series of attacks are likely to have been masterminded by the same people.
There is speculation that the unused explosives police recovered from various sites including a hire car abandoned by the July 7 bombers at Luton might have forced the latest group of bombers to cobble something together fairly quickly.
Yesterday's bombs might suggest something else, namely that the terrorists "have planned a campaign, not just one bomb," Mr Clarke said. "It's part of terrorist psychology that one bomb is never enough. You gain the effect that you want by creating a sense that there are lots of bombs and the public are going to have to live with this for a long time."
"It could be that this is a nasty sort of copycat attack mimicking what happened two weeks earlier but not using quite the power of explosives, but still getting the chaos and fear effect as you can see around us," said Crispin Black, a former British government intelligence analyst.