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Investigation: Protecting the nation's transportation system

Attorney General John Ashcroft speaking at a recent news conference.

SUMMARY:

State officials from California to New York scrambled Saturday to protect the nation's transportation system in the wake of the protracted state of "high alert" that Homeland Security Director Tom Ridge issued this week.

The increased security follows possible new threats, such as a warning of attacks announced by California Gov. Gray Davis on four of his state's bridges, and reflects a new reality following the September 11 terrorist attacks on New York and Washington.

Officials acknowledged they cannot safeguard every key transportation structure but said they would try to protect the nation's most critical ones.

UPDATE:

FBI agents, many wearing oversized hazardous materials suits, raided an apartment in Trenton, New Jersey, Friday, bringing out bags of seized materials and taking one man in for questioning. FBI agents and local police arrived at the first-floor apartment about 9 a.m. ET, according to neighbors. (Full story)

Attorney General John Ashcroft on Friday retracted a claim he made during a news conference Wednesday that three men arrested in Detroit had knowledge of the September 11 terrorist attacks. (Full story)

Ridge, asked if the non-specific threat that sparked the alert was still thought to involve only this week, he said, "We're going to keep everybody on the Monday alert -- that attentiveness -- indefinitely." He acknowledged that officials may not be able to identify and detain all terrorists here and abroad. "The world has changed since September 11," he said. (Full story)

The Justice Department called the threats to the California bridges "uncorroborated," and some officials criticized the California governor for causing undue alarm. Davis on Friday defended his decision to go public with the warning, saying he "acted on three written warnings from three federal offices." (Full story)

The FBI has resolved questions about the identities of the 19 hijackers involved in the September 11 attacks and has discovered places outside the United States where the conspiracy was planned, FBI Director Robert Mueller said Friday.

•  Summary   •  Update   •  Key questions   •  Who's who   •  Impact

CNN.COM SPECIAL REPORT  CNN NewsPass Video  Agencies reportedly got hijack tips in 1998  MORE STORIES Intelligence intercept led to Buffalo suspects Report cites warnings before 9/11  EXTRA INFORMATION Timeline: Who Knew What and When? Interactive: Terror Investigation Terror Warnings System Most wanted terrorists What looks suspicious? In-Depth: America Remembers In-Depth: Terror on Tape In-Depth: How prepared is your city?  RESOURCES On the Scene: Barbara Starr: Al Qaeda hunt expands? On the Scene: Peter Bergen: Getting al Qaeda to talk

VIDEO Saudi officials say they have found 'no direct evidence' of financial support for terrorists. CNNfn's Allan Dodds Frank reports (October 31) Play video (QuickTime, Real or Windows Media)

Friday morning traffic rolled across the Golden Gate Bridge, with National Guard members dispatched to the Bay area by Davis to supplement security provided by the California Highway Patrol and the U.S. Coast Guard. (Full story)

As part of the effort to track down terrorists, Ridge also told reporters Friday that he is working to help government agencies consolidate their intelligence databases.

Information from the Immigration and Naturalization Service, the State Department and the FBI is being collected and will be housed in the office of the attorney general, Ridge said. (Full story)

Saudi Arabian officials and others have questioned whether some of the hijackers identified by the FBI in the weeks after the attacks used stolen identifications. Mueller said those questions have been answered.

"We at this point definitely know the 19 hijackers who were responsible," he said. "We have been successful in working with our foreign counterparts in identifying places where the conspiracy we believe was hatched as well as others who may have been involved in the conspiracy."

Mueller provided no new information on the hijackers' identities beyond his statement at a briefing Friday for reporters. Neither did he name any of the places abroad where authorities now believe the conspiracy was initiated, or any of the other conspirators.

Officials say the new Operation Green Quest -- a multi-agency effort led by the Customs Service -- will probe such areas as counterfeiting, credit card fraud, fraudulent import and export schemes, drug trafficking, cash smuggling and other activities that could be used by al Qaeda and other terrorist groups for financing their operations.

Investigators will use undercover operations, electronic surveillance, intelligence data and other resources to uncover underground financial systems, illicit charities and corrupt institutions that may be raising money for terrorists here at home and abroad. (Full story)

KEY QUESTIONS:

What tactics are being used to get people in custody to talk about any knowledge they may have of the September attacks?

What avenues are international investigators pursuing to trace the source of funding for the suspected hijackers? Click here for more.

What clues about the September 11 attacks have U.S. investigators learned from the hundreds of arrests made?

How will the expansion of law-enforcement powers affect Americans' civil liberties? Click here for more.

How long can suspects be held, and on what charges are they being held? Click here for more.

What groups are U.S. investigators focusing on, and what are their aims? Click here for more.

WHO'S WHO:

George W. Bush: U.S. president

Colin Powell: U.S. secretary of state Click here for more

Condoleezza Rice: National security adviser Click here for more

John Ashcroft: U.S. attorney general

Robert Mueller: FBI director Click here for more

George Tenet: CIA director. Click here for more

Osama bin Laden: U.S. authorities have named bin Laden, a wealthy Saudi exile living in Afghanistan, as the prime suspect in masterminding the September 11 attacks. Click here for more

IMPACT:

Information gained from the investigation could lead to fundamental changes in U.S. security and intelligence systems, as well as surveillance laws.