From a July 12 Radio Free Europe report on the first arrest in the case:

The arrested man is thought to be a relative of one of the main suspects. The present whereabouts of all the main suspects is unknown: police are considering the possibility that one or all of them were killed in the bomb blasts.

But the most ominous news is that authorities believe most of the suspects were of Pakistani origin but born in Britain and raised in the provincial city of Leeds in Yorkshire. One of the bombers is thought to be from Luton, an industrial town just north of London. Both cities have large Muslim populations.

If these facts are correct, the implications are grave indeed.

It would mean that instead of having to deal with a handful of foreign terrorists who arrived in England on a single terrorist mission, the British authorities are facing a domestic terror scene that has been able to secretly nurture, train, and equip British citizens for a major attack on one of the world's great cities -- all under the noses of the police and intelligence communities.

London-based security analyst Chris Langton of the International Institute for Strategic Studies says the events are a setback for national security.

"This is a blow to the security of the country in that this happened without anybody being aware that it was imminent -- particularly because the extensive surveillance and intelligence-gathering activities that have gone on over the last months have been successful in many other ways, in preventing attacks," Langton said.

Analysts say it's too early to conclude that Britain already has a fully developed terror network. But some -- like London-based security consultant Crispin Black -- say it's fairly obvious the bombers had access to expertise, probably from overseas.

"I don't accept the story that these [young men] would spontaneously turn into suicide bombers and carry out a do-it-yourself operation in London. I think they have technical support from a bomb maker, and command and control [links] from someone else," Black said.