WASHINGTON – U.S. officials began piecing together a case linking Osama bin Laden to the worst terrorist attack in U.S. history, aided by an intercept of communications between his supporters and harrowing cell phone calls from victims aboard the jetliners before they crashed on Tuesday.

Authorities were focusing some of their efforts on possible bin Laden supporters in Florida based on the identification of a suspected hijacker on one of the manifests of the four jets that crashed, law enforcement sources said.

The sources said the FBI was preparing to search locations in Broward County in south Florida and Daytona Beach in central Florida. The locations had links to the suspected bin Laden supporter on the jet manifest, the officials said.

U.S. intelligence intercepted communications between bin Laden supporters discussing the attacks on the World Trade Center in New York and the Pentagon, according to Utah Sen. Orrin Hatch, the top Republican on the Senate Judiciary Committee.

“They have an intercept of some information that included people associated with bin Laden who acknowledged a couple of targets were hit,” Hatch said in an interview with The Associated Press. He declined to be more specific.

Hatch also said law enforcement has data possibly linking one person on one of the four ill-fated flights to bin Laden’s organization.

Government and industry officials said at least one flight attendant and two passengers called from three of the planes as they were being forced down in New York and Washington – each describing similar circumstances involving knife-wielding hijackers

The callers indicated hijackers armed with knives, in some cases stabbing flight attendants, took control of the plane and were forcing them down toward the ground, officials said.

One of the passengers was Barbara Olson, the wife of Solicitor General Theodore Olson, who called her husband as the hijacking was occurring. She was aboard American Airlines Flight 77 that left Dulles International Airport in Washington and was forced to crash into the Pentagon.

The officials said Olson told her husband the attackers had used knifelike instruments to take over the plane, and forced passengers to the back of the jet.

Theodore Olson confirmed his wife made the calls before dying. “She called from the plane while it was being hijacked. I wish it wasn’t so but it is,” he said.

Separately, a businessman, his wife and young child aboard a United flight that left Boston and crashed into the World Trade Center twice called his father in Connecticut as his plane was being hijacked, a law enforcement official told The Associated Press.

The official, speaking on condition of anonymity, said the victim’s father told the FBI his son made two calls, and both times the phone cut off. In the first call, the businessman said a stewardess had been stabbed. In the second call, the son said his plane was going down.

The man was identified as former Easton, Conn., resident Peter Hanson.