Four material witnesses under arrest

The FBI investigation of last week’s terrorist attacks has led to the arrest of four people as material witnesses and, aided by a federal grand jury, is seeking more people who may have information about the plot, law enforcement officials said today.

One of the four material witnesses is Albader Alhamzi, 34, a Saudi national and Saudi-trained doctor who was doing a medical residency in radiology at University of Texas Health Science Center, said one of the government officials, speaking on condition of anonymity. He is being held in New York.

Authorities also detained a man in San Diego, Calif., who was linked through financial transactions to two of the 19 hijackers, officials said. They declined to say whether he was arrested as a material witness.

As U.S. law enforcement officials pull in more people for questioning, a federal grand jury has been convened to investigate the terrorist attacks that destroyed the World Trade Center, The Associated Press has learned.

The grand jury in White Plains, a suburb north of New York, will review evidence and issue subpoenas, according to a law enforcement source who spoke on condition of anonymity.

Attorney General John Ashcroft stressed the urgency of the moment Monday by saying that associates of the hijackers “may be a continuing presence in the United States.”

“It’s very likely there was significant ground support and reinforcement assistance from collaborators” for last Tuesday’s four teams of terrorists, Ashcroft said on CNN’s “Larry King Live” program.

As of Monday, the FBI had detained 49 people for questioning, holding them on immigration violations, double the number of several days ago. Some have asked for lawyers, and none has been charged in the attacks that may have killed more than 5,000 people.

In addition, authorities are looking for nearly 200 other people to question in last Tuesday’s attacks on New York City’s World Trade Center and the Pentagon.

The FBI is keeping a tight hold on its witnesses, jailing an unspecified number of them because they might otherwise flee. The Justice Department previously confirmed two people were arrested on such warrants. Courts have sealed all information about those arrested.

Asked to characterize whether those in custody are talking, FBI Director Robert Mueller said that “there are individuals cooperating, yes,” while adding that others are not.

Federal agencies are being asked to contribute armed plainclothes security officials while the Federal Aviation Administration begins to train a new generation of marshals to provide security on airplanes. Four jetliners were hijacked in last week’s attacks. Two were crashed into the World Trade Center, a third into the Pentagon and a fourth crashed in southwestern Pennsylvania after passengers apparently struggled with hijackers.

U.S. officials have said Saudi Arabian exile Osama bin Laden and his al-Qaeda organization are the prime suspects in the attacks. Bin Laden has denied any responsibility.

Ashcroft outlined the sky marshals plan along with additional details of the legislative package he asked Congress to pass immediately. It would include use of the money-laundering statutes to prosecute people who provide resources to a terrorist organization. The package also included nationwide wiretap authorization so that when a suspected terrorist moved around the country, law enforcement agencies wouldn’t have to get additional court approval for a wiretap in a different jurisdiction.

Additional detail emerged about one of the hijackers and possible associates.

Hani Hanjour, suspected of crashing American Airlines Flight 77 into the Pentagon, trained at a flight school in Bowie, Md., flying small planes over the Washington area at least three times in the six weeks prior to last Tuesday’s attack.

Chief flight instructor Marcel Bernard said Monday that Hanjour wanted to demonstrate his flying competency. But the airport used by the flight school wouldn’t rent planes to Hanjour for solo flights because of doubts about his flying skills and his refusal to provide an address and phone number.

FBI agents pressed to learn whether any of those already in custody may have assisted the hijackings, were thwarted in their own efforts to hijack other planes or planned to carry out other attacks against Americans.

Among those being detained are two men who left on a plane from Newark, N.J., around the time of the attacks and then took an Amtrak train to Texas from St. Louis after their plane was grounded as part of the government-ordered shutdown of the U.S. aviation system.

Ayub Ali Khan, 51, and Mohammed Jaweed Azmath, 47, were removed from an Amtrak train during a routine drug search Wednesday night. No drugs were found, but the men had box-cutting knives and about $5,000 in cash, according to a federal official who spoke on condition of anonymity.

Hijackers in Tuesday’s attacks used knives and box cutters to commandeer the four airliners.

The FBI is aggressively questioning their acquaintances in New Jersey, where at least 13 people are being detained, officials said. Agents also raided apartments and questioned several people in a New Jersey neighborhood that was once home to blind sheik Omar Abdel-Rahman, convicted of plotting the 1993 bombing of the trade center and other New York landmarks.

Khan and Azmath have been flown by authorities to New York, as was another man, Zacarias Moussaoui, who had been held in Minnesota, officials said.

Retired CBS news anchorman Walter Cronkite called for the immediate appointment of a censorship board to monitor the strict secrecy that Ashcroft has announced. Cronkite said that secrecy is necessary in the war against terrorism, but that the government should immediately appoint a board of journalists and historians that will be aware of all the government’s plans and actions. Secrecy must not be used to protect political decisions or government failures, but only for military purposes, Cronkite said.