A federal judge’s decision today — excluding key testimony from the first civilian trial of a Guantanamo detainee — is the latest, and potentially most significant, in a series of government losses in Gitmo-related cases that relied on evidence gained during coercive interrogations.

Ahmed Khalfan Ghailani, accused of participating in the 1998 al-Qaida bombings of U.S. embassies in Kenya and Tanzania, had been set to go on trial Wednesday in Manhattan. Judge Lewis Kaplan’s ruling blocks prosecutors from calling a witness, Hussein Abebe, who was expected to testify that he had sold Ghailani the explosives used in one of the attacks. Prosecutor Michael Farbiarz had called Abebe a “giant witness for the government.”

Judge Kaplan postponed the trial until Oct. 12 while the government considers whether to appeal the ruling. Read entire story here.