A translator says Osama bin Laden names some of the September 11 hijackers in the tape released last week by the US Government.
Mr George Michael, who has made a more thorough translation of the tape, says bin Laden commends the terrorists to God.
He says the tape comes up with "a whole bunch of names", including Nawaq Alhamzi, Salem Alhamzi and Wail Alshehri.
Alshehri was on American Airlines flight 11, one of the planes that hit the World Trade Centre, while the two Alhamzis were on American Airlines flight 77, which hit the Pentagon.
The Pentagon released the first transcript last week, offering a glimpse of terrorist planning as bin Laden told his aides and clerics that the deaths and destruction achieved by the September 11 attacks exceeded his "most optimistic" expectations.
Mr Michael said the names have only now emerged because the first translation was rushed in 12 hours. It took four days to complete the fuller transcript.
He added references bin Laden made in the original transcription of the tape already tie him to the attacks - but naming and blessing the hijackers suggests an intimacy that would reinforces US claims of his deep involvement in the planning.
Lebanese-born Mr Michael translated the tape with Mr Kassem Wahba, an Egyptian. Both men had difficulties with the Saudi dialect bin Laden and his guest used in the tape.
Some passages remain a mystery, Mr Michael said: Bin Laden's Saudi guest names the person who smuggled him from Saudi Arabia into Afghanistan.
Mr Michael and Mr Wahba, however, are unable to make out the name.
PA