Several of the hijackers who carried out the September 11 terrorist attacks used computers and the Internet at public libraries, a law enforcement official revealed yesterday.

A U.S. attorney for the District of Columbia, Kenneth Wainstein, told the House Judiciary Crime, Terrorism, and Homeland Security Subcommittee that investigators discovered that three of the hijackers had used computers in a public library at Delray Beach, Fla. Two other terrorists used computers at a state college library in New Jersey. They used the Internet there to make reservations on one of the planes that crashed into the World Trade Center, Mr. Wainstein said.

The chairman of the House Judiciary Committee, Rep. James Sensenbrenner, a Republican from Wisconsin, said the disclosures underlined the importance of Section 215 of the Patriot Act, which gives law enforcement agents the ability to access any “tangible things” – including the business records of medical offices, libraries, gun stores, and other businesses – with minimal judicial review.

“Today we learned the 9/11 murderers used our public libraries to access the Internet and help plan their travel prior to 9/11,” Mr. Sensenbrenner said in a statement. “We put Americans’ lives at risk if we foolishly provide sanctuaries – even in our public libraries – for terrorists to operate.”

The president of the American Library Association, Carol Brey-Casiano, responded that the Patriot Act was not responsible for the discovery that terrorists frequented the Delray Beach library branch. Instead, it was because the librarian there had seen a picture of the terrorists and relayed the information to federal investigators.

“Like all Americans, librarians are concerned about our nation’s security. Even so, targeting libraries won’t make us safer,” Ms. Brey-Casiano said. “Because the USA Patriot Act does not require the FBI to name an individual or to give specific reasons to believe he is engaged in terrorism, Section 215 has the potential to open patrons’ reading and research records to a fishing expedition.”

According to the American Civil Liberties Union, which has challenged the constitutionality of section 215 in a case pending in federal court, Attorney General Gonzales has said Section 215 has been used at least 35 times.

“Portions of the Patriot Act further weakened the already loosened protections against the abuse and misuse of FISA,” the associate director of the ACLU Washington legislative office, Gregory Nojeim, said in a statement, referring to the Foreign Intelligence Surveillance Act, which authorizes the searches warranted by section 215. “Lawmakers must make sure that FISA is not a means for law enforcement to unnecessarily invade the privacy of Americans.”