Officials confirmed yesterday that two of the suspected hijackers flew to Boston from Portland, leaving behind a rental car with Massachusetts plates. However, it remained unclear how the suspects passed through Logan security, and officials adamantly refused to discuss details of the investigation.

“It does not help efforts to put together a solid, sustainable case...to discuss at this point what facts law enforcement may or may not know,” Acting U.S. Attorney James Farmer said.

FBI officials began to pursue bin Laden’s many ties to the Boston area, where his brothers own property and one of them donated money to Harvard University.

Investigators were also interviewing drivers from a Boston cab company which used to employ two bin Laden associates, one of whom was jailed in Jordan on charges of plotting to blow up a hotel full of Americans and Israelis.

The FBI interviewed drivers of the Boston Cab Co. to investigate whether cab drivers had ties to Logan Airport baggage handlers who may have helped carry out the terrorist plot in New York, former FBI supervisor Robert Fitzpatrick told the Associated Press.

“They could thwart the security by having a baggage handler put the material aboard the plane. That link is being investigated,” he said.

Federal authorities also seized a white Mitsubishi in the garage at Logan Airport that had been rented at an Alamo office just off the airport, said Cheryl Budd, senior vice president for corporate communications for Alamo’s parent company.