The person, identified only as a confidential witness, is one of two persons approved during a hearing to testify in the trial of Sulieman Abu Ghaith, which will begin in a few weeks, Courthouse News Service reported Wednesday.
The confidential witness, who will testify for the prosecution, was described as having been arrested and convicted in the United Kingdom in 2003 in connection with an al-Qaida plot "to detonate a shoe bomb on a transatlantic airplane."
That description appears to fit Saajid Badat, a British citizen and alleged co-conspirator of Reid, who is serving three life sentences in a federal prison for attempting to set off a bomb hidden in his shoe on an American Airlines flight in 2001.
A British prosecutor says Badat has renounced extremism. The BBC has reported Badat has had his sentence reduced in exchange for testifying "in a forthcoming terror trial in the U.S."
U.S. District Judge Lewis Kaplan, who is presiding over Ghaith's trial, said Badat will testify by way of a video link from Britain because he is wanted in Massachusetts.
Kaplan also approved Salim Hamdan to testify as a defense witness.
Hamdan, bin Laden's driver, was convicted in Guantanamo of providing material support for terrorism. He was released five months later and his conviction was vacated late last year.
He is expected to testify on "brevity cards," which Kaplan's ruling said were used by al-Qaida and contained "coded names and locations of certain individuals."
The ruling said Hamdan would testify that a person's name on a brevity card did not necessarily indicate "membership or allegiance to al-Qaida."
Prosecutors say they plan to prove Ghaith's name appeared on one.