LONDON - The investigation into a plot to blow up jetliners over the Atlantic 
zeroed in Saturday on brothers arrested in Pakistan and Britain, one named as a 
key al-Qaida suspect who left the family's home in England years ago and the 
other described as gentle and polite. 
 British authorities, meanwhile, warned against complacency, 
saying the detention of several dozen suspects had not eliminated the danger. 
The terror threat level in Britain remained "critical"- its highest designation - and 
delays, flight cancellations and intense security continued to greet travelers 
at London airports. 
"No one should be under any illusion that the threat ended with the recent 
arrests. It didn't," Home Secretary John Reid told police chiefs at a breakfast 
meeting. "All of us know that this investigation hasn't ended." 
Among the questions British police are studying is whether any of the 
suspects had links to last year's London suicide bombers and how many visited 
Pakistan in recent months. They also are examining Internet cafes near the 
suspects' homes, looking into the possibility of tracking Web based e-mails or 
instant messages, Scotland Yard said. 
With US authorities urgently investigating whether the British plotters had 
ties in America, a news report said at least one of the men under arrest in 
Britain had contact in Germany with the wife of Sept. 11 fugitive Said Bahaji. 
The report in Focus, a German weekly, did not specify the suspect involved or 
say when the contact occurred. 
British investigators and officials have not said how 
close the plot was to fruition when the arrests were made, but US officials have 
said they would not have likely waited as long. 
In June, US law enforcement officials arrested seven young men in Miami, 
claiming they'd plotted to bomb the Sears Tower in Chicago and a federal 
building in Miami. 
"You want to go and disrupt cells like this before they acquire the means to 
accomplish their goals," US Attorney R. Alexander Acosta said. 
One intelligence veteran suggested cultural and legal differences could 
account for why British authorities are more willing than their American 
counterparts to watch and wait before making a move in a terror case. 
"It's just the way they work," said Stan Bedlington, of 
Arlington, Va., a former CIA senior terrorism analyst who also served in the 
Special Branch intelligence services of the British Colonial Police. "They 
(British) would always hope that they could turn somebody and use them to their 
advantage," he said.