The Second Plot: Copycats or Co-Conspirators?

LONDON — They were two terrorist cells united by, if nothing else, the same target: the London transport system.

By the time the first bombers reached their targets on the morning of July 7, three of them had traveled 200 miles.

Exactly two weeks later, the second group struck just 200 yards from a ground-floor apartment where one suspect lived with his wife and three children.

The two groups of young men were separated by more than miles. Three of the July 7 bombers were British-born sons of a Pakistani immigrant community that has carved out a solid life in the weary industrial neighborhoods of Leeds in Britain's north. One was a schoolteacher; another worked in his father's fish-and-chips shop.

In contrast, at least three of the July 21 suspects came to Britain hardened by youthful odysseys out of the despair of Somalia, Eritrea and Ethiopia. They never got past the margins of British society, sliding into a gray world of unemployment, welfare, public housing and crime.

Yet authorities say they came to the same violent conclusion: wreaking havoc in the capital by attacking three Underground trains and a bus with backpack bombs. The first plot killed 56 people, including the bombers. The second could have inflicted the same carnage, but the explosives failed to fully detonate because of a bomb maker's mistake, police say.

Police were trying to make sense of the differences and similarities Saturday as they questioned four July 21 suspects and another London man thought to be a possible fifth would-be bomber.

Detectives confront a fundamental mystery: Were the two plots part of a terrorist campaign by an international network that cobbled together multi-ethnic cells from different cities and disparate backgrounds? Or was the second strike a copycat attack by an unrelated group, as Italian police say one of the July 21 suspects said in a confession Friday?

Despite the reported confession and the contrasts between the Leeds and London cells, most investigators think there has to be a link because of the remarkably similar explosives, targets and methods.

"I think there's plenty of linkage," said a British anti-terrorism official who spoke on condition of anonymity. "Two attacks within two weeks with very similar modus operandi. The significance of that alone shouldn't be discounted. What has to be determined is how those linkages work."