The investigation into an alleged plot to blow up jetliners over the Atlantic zeroed in Saturday on brothers arrested in Pakistan and Britain – one who left the family's home in England years ago and another who was described as gentle and polite.
As investigators track the brothers' lives, increasingly they are examining links to al Qaeda — focusing on connections in Pakistan, reports CBS News correspondent Sheila MacVicar.
On Wednesday, Pakistani authorities arrested one brother, Rachid Rauf. After his arrest, Security sources told MacVicar, a phone call was made, back to the plotters in the Britain.
The message? Act now before you can be stopped. U.S. and British intelligence intercepted that call. It was what triggered the decision for British police to move in.
Rashid Rauf was arrested along the Pakistan-Afghan border, and Pakistani officials have characterized him as a "key person" in the airline plot. They said evidence linked him to an "Afghanistan-based al Qaeda connection" but gave no details.
His brother, Tayib, Rauf was one of the men arrested in Britain on Thursday.
The Rauf's father, Abdul, immigrated to Britain from the Mirpur district of Pakistan several decades ago, and his five children were all born in Britain, the family said.
A great-uncle of the Rauf brothers said Tayib is partially deaf due to a childhood illness.
"He is very, very polite, the kindest person you could hope to meet," Qazi Amir Kulzum was quoted as saying in Saturday's edition of the Birmingham Post. "No one can believe that he would be involved in such matters."
Neighbors and friends of the Raufs expressed shock that the brothers were caught up in the inquiry, but the devout Muslim family is no stranger to authorities.
The Raufs' terraced home was first searched during a 2002 investigation into the fatal stabbing of Mohammed Saeed, an uncle of the brothers, police said. Rashid Rauf was reportedly a suspect in the slaying and is thought to have left England for Pakistan shortly after the death.
The house was searched again in connection with a murder during race riots in 2005.
Seventeen of those now in British custody have ties to Pakistan, and some have recently traveled there, reports MacVicar.
In Islamabad, where authorities are eager to put a positive spin on a story that has again put Pakistan at the center of a major international terror investigation, officials spent Saturday leaking details of their country's role in cracking the case.
"The arrests took place following very close co-operation between the three countries. In fact Pakistan played a very important role," Tasnim Aslam, a Pakistan foreign ministry spokeswoman, told MacVicar.
Pakistan is questioning dozens of people, including Rashid Rauf and one other British national whose name has not been released.
While authorities in Pakistan believe they have nabbed the main players in the plot, the second intelligence official said two or three suspects remained at large, including Matiur Rahman, a senior figure in the al Qaeda-linked Pakistani militant group Lashkar-e-Jhangvi. He said Rahman's name was mentioned by one of the detainees during interrogation.
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."
With U.S. 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.
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.
One of the suspects, Don Stewart Whythe, may be the most unusual of the 23 still under investigation. He's the son of a former British political worker, shared a home with is mother, and according to friends never showed signs of violence, reports CBS News correspondent Randall Pinkston.
"I've known this guy four years straight. He's too much of a nice guy, too much of a nice guy. He got married less than a month ago," one young man told Pinkston.
Wythe was a convert to Islam who changed his name to Abdul Waheed.
"Converts are the terrorists of the future," forensic psychiatrist Michael Welner told Pinkston. " Because they 're impressionable, because they're intense, because they have to prove the sincerity of their faith."
British authorities have released little information about the course of their investigation into the alleged terror plot in general. There were no briefings Saturday for the second straight day, and senior government figures stayed largely out of sight.
The British government warned news media not to put the investigation at risk by publishing details about the plot. Reid, the home secretary, and Attorney General Lord Goldsmith called for "considerable restraint" to avoid tainting any trials.
They said the government was trying to "strike the balance between the need to provide necessary information to the public and to business whilst avoiding prejudicing ongoing investigations or future proceedings."
British investigators and officials have not said how close the plot was to fruition when the arrests were made, but U.S. officials have said they would not have likely waited as long.
"You want to go and disrupt cells like this before they acquire the means to accomplish their goals," U.S. 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 (the British) would always hope that they could turn somebody and use them to their advantage," he said.
But he said he believed that the ability of the British to round up suspects without bringing formal charges helped them wait longer.
"In America, they're very much afraid of an operation going down before they can stop it. It's a matter of culture," Bedlington said.