* Courtroom feed was cut at mention of secret CIA prisons
* Judge said no outside party had authority to suspend broadcast
* Defense wants probe of suspected monitoring of talks with clients
By Jane Sutton
GUANTANAMO BAY U.S. NAVAL BASE, Cuba, Jan 31 (Reuters) - A U.S. military judge on Thursday ordered the government to dismantle a monitoring system that let outside censors halt the public broadcast of hearings for Guantanamo prisoners accused of plotting the Sept. 11 attacks.
The closed-circuit broadcast feed was cut for a few minutes during a pretrial hearing at the Guantanamo Bay U.S. Naval Base on Monday for the self-described mastermind of attacks, Khalid Sheikh Mohammed, and four co-defendants.
The cutting of the feed revealed for the first time that a still unidentified entity outside the courtroom was listening in to proceedings with a finger on the kill switch. The judge, Army Colonel James Pohl, was incensed.
"It is the judge that controls the courtroom," Pohl said in giving his ruling. "This is the last time ... any other third party will be permitted to unilaterally decide that the broadcast should be suspended."
The feed was cut when Mohammed's lawyer, David Nevin, mentioned a defense request to preserve the secret CIA prisons where the defendants had been held before being brought to Guantanamo.
Pohl said on Tuesday the feed had been cut without reason because the information in question was not secret, and a transcript of the censored portion was later released.
Spectators watch tribunal hearings from behind a soundproof glass wall at the rear of the courtroom at Guantanamo. They hear the sound on a 40-second delay, through a feed that also provides sound and video to journalists in the Guantanamo press center and to a couple of closed-circuit viewing sites on the U.S. East Coast.
A court security officer sitting next to the judge controls a button that muffles the feed with static and flashes a red light when secret information is disclosed.
After meeting privately with the lawyers, including prosecutors who seemed well aware of the outside monitoring, Pohl said an "original classification authority" had the ability to monitor the courtroom and cut the feed.
Pohl did not identify that authority but it would be whichever agency or officer had originally classified information about the CIA prisons as secret.
Pohl ordered that monitoring system be removed on Thursday and said emphatically that he and the court security officer were the only ones with authority to suspend the broadcast.
The chief prosecutor, Brigadier General Mark Martins, is the government's top-ranking representative at the trial and said his team would comply with the judge's order. He refused to say who cut the feed or where they were listening from.
The hearings adjourned as scheduled on Thursday and will resume on Feb. 11.
They will then consider an emergency request that further hearings be halted until it can be ascertained whether someone was also eavesdropping on defense attorneys' conversations among themselves and with their clients. Nevin said defense lawyers have a duty to ensure those are confidential.
Defense lawyers have long suspected their conversations were being monitored and "after this week, the paranoia level has kicked up a notch," said James Connell, who represents defendant Ali Abdul Aziz Ali.
After Thursday's hearing, another of the defense lawyers, Commander Walter Ruiz, said: "Is this a system that we can believe in? Who is pulling the strings? Who is the master of puppets?"
The defendants are charged with training, funding and aiding the al Qaeda hijackers who slammed commercial jets into U.S. buildings in 2001, killing 2,976 people. They could be executed if convicted of charges that include murdering civilians, terrorism and hijacking. (Editing by Kevin Gray and David Brunnstrom)