As the search for evidence continues after Thursday's London blasts, experts feel the unexploded devices will provide a wealth of clues.
Police are appealing for help from witnesses of the failed attacks
Similarities between the latest attacks and those of 7 July suggest there might be a connection.
Detailed chemical analyses are expected to reveal why the bombs did not go off.
Investigators also hope to get help from a number of passengers who witnessed the failed attacks and described the suspects to the media.
Early indications suggest Thursday's incidents and those of a fortnight ago may have been masterminded by the same group.
Clues pointing in this direction include the type of rucksacks used to carry the bombs around, the chosen targets - three Tube trains and one bus at compass points on the travel network - and the type of explosive itself, said the BBC's Mark Urban.
The head of the Metropolitan Police, Sir Ian Blair, said the new attacks were meant to cause mass casualties.
But why did all the devices fail to detonate?
Speaking on BBC Two's Newsnight programme, Mike Granatt - a government counter-terrorism adviser - said the science of bomb making was not precise.
"People who are doing things in a hurry and under tension get things wrong - and thank God they appear to have got things wrong," he said.
He added that the clues left behind by the bombers, including fingerprints on the rucksacks, might provide investigators with a "forensic goldmine".
"Unlike the fingertip forensic search we saw in Tavistock Square which went on for days, they (the police) have got something complete, they've got the fingerprints on there possibly," he said.
"They've got other material on there, they can take a look at it, compare it and try and trace back the materials that were used to make the bomb and indeed the signature of the bomb maker."
Former government intelligence analyst Crispin Black said the chance to examine the bombs themselves was "forensic bingo", saying: "This is as good as it gets."
In addition, Dame Pauline Neville Jones - who formerly chaired the Joint Intelligence Committee - believes the forensic trail would "lead back to real knowledge".
But she warned that tracking down the terrorists might take a long time.
"You build up an intelligence picture of something which is as complex and as potentially widespread as the sort of threat that we face only slowly and only very carefully," she told Newsnight.
"I think the resources will be thrown to this task in a manner which means that we won't allow ourselves years to do it."
Thousands of police officers are involved in the hunt.
Roy Ramm, former Commander of Specialist Operations for the Met police, said police had an amazing opportunity to find the bombers.
"These devices haven't detonated so the evidence remains intact," he said.
"They'll want to take these bombs apart in most minute details. They'll be looking at everything from sticky tape that may have held a detonator to the bomb to see if there's fingerprints on the back of that.
"They'll be looking for fragments of DNA - we know that people have been convicted of robbery on one hair or fragment of dandruff - so these are very powerful investigative tools."
Police will be hoping that numerous apparent sightings of the suspects will also help boost the investigation.
Each of the failed bombings were witnessed by passengers.
Several of them described the attackers as "scared" or "surprised" as their bombs failed to cause a proper explosion.
Kate Reid, who was involved in the Oval accident, said she was on the train when she heard a "pop" as if a big balloon had burst before seeing a young-looking, dark-skinned man with a bag at his feet who looked "really scared".
Witnesses also described how the suspects were chased by other passengers as they made their way to the exits.
One passenger told BBC News that he put his foot out to try to trip one of them up but failed.
Another, Hugo Palit, who was walking into Warren Street Tube station, said he saw "a guy coming out and people chasing him".
He described him as "a bit confused, looking right and left".