The first civilian trial for a Guantanamo Bay detainee has been delayed after a US judge told prosecutors they could not call their star witness.
US District Judge Lewis Kaplan blocked the government from calling a man who authorities said sold explosives to the defendant, Ahmed Khalfan Ghailani.
Defence lawyers say investigators only learned about the witness after Ghailani underwent harsh interrogation at a secret CIA-run camp overseas between 2004 and 2006.
"The court has not reached this conclusion lightly," Kaplan wrote. "It is acutely aware of the perilous nature of the world in which we live. But the Constitution is the rock upon which our nation rests. We must follow it not when it is convenient, but when fear and danger beckon in a different direction."
The government immediately asked for a delay of the New York trial, which had been expected to begin with opening statements, so that it has time to appeal against the ruling, should it decide to do so.
The judge sent a pool of 66 jurors home until Tuesday, but not before warning them against hearing anything about the case from news reports or discussing it with anyone.
Ghailani is charged with conspiring in the 1998 bombings of two US embassies in Africa. The attacks killed 224 people, including a dozen Americans.
He was smiling and talking with his lawyers at the defence table after the judge's ruling.
The judge issued his written three-page ruling after a hearing three weeks ago in which the witness, Hussein Abebe, testified about his dealings with authorities.
"The government has failed to prove that Abebe's testimony is sufficiently attenuated from Ghailani's coerced statements to permit its receipt in evidence," Kaplan wrote.