Moans, sighs and exclamations erupted Saturday as relatives of Sept. 11 victims watched four closed-circuit TV feeds from Guantanamo Bay, Cuba, that showed the self-proclaimed mastermind of the attacks and co-defendants trying to slow their arraignment, a move that drew outbursts from viewers of “c’mon, are you kidding me?’’

“It’s actually a joke, it feels ridiculous,’’ said Jim Riches, whose firefighter son, Jimmy, died at the World Trade Center. Riches watched the hearing from a movie theater at Fort Hamilton in New York City, one of four U.S. military bases where the arraignment was broadcast live for victims’ family members, survivors and emergency personnel who responded to the attacks.

Khalid Sheikh Mohammed and the other defendants were arraigned on charges that include terrorism and murder, the first time in more than three years that they appeared in public. During the hearing, they generally refused to cooperate. At one point, one detainee leafed through a copy of The Economist magazine, then passed it to another. At other times, defendants knelt in prayer.

Like other family members, Riches expressed frustration about the proceedings.

“It’s been a mess for 11 years,’’ Riches said as he stood in the rain during a break in the proceedings and described the atmosphere inside. And after his first glimpse inside the military courtroom, he said, “It looks like it’s going to be a very long trial. … They want what they want.’’

Riches, himself a retired firefighter who worked digging up remains in the days after Sept. 11, said he carried with him dark memories of the days after the attacks, and he hoped that if convicted the five men would be executed.

“I saw what they did to our loved ones — crushed them to pieces,’’ he said.