They walked slowly, hobbled by age more than by the clinking ankle and waist chains they wore as they entered the federal courtroom. But by no means could they be considered weak, at least not in a prison-culture sense. Like murder victim Manuel “Tati” Torrez, 63, the three trial witnesses had earned reputations for ruthlessness by leading the most violent prison gangs in America: the Aryan Brotherhood, the Mexican Mafia and the Black Guerilla Family.

The U.S. Bureau of Prisons had placed each of them in Florence in the Administrative Maximum U.S. Penitentiary, the highest security prison in the United States, or “Supermax,” after labeling them and some 415 others the most dangerous prisoners in the federal system.

Their testimony was intended to persuade jurors in the first-degree murder trial of Silvestre “Chikali” Rivera, 57, that prison culture dictated that he either stomp Torrez to death on April 21, 2005, or be killed himself.

The jury didn’t buy the argument and found him guilty on April 21, the 10-year anniversary of the murder, rejecting the premise that prisoners should be tried under different standards because of the unique characteristics of Supermax. Rivera will spend the rest of his life in prison.

But while they spoke matter-of-factly about bloody hand-to-hand combat with cell-made knives, they characterized a hierarchy of leadership similar in some ways to the military or mainstream society.

Prison etiquetteThough prison is largely a young man’s world, gang members called “soldiers” take their orders from silver-haired “shot-callers” who decide who pays cell-house “rent” to stay safe, and who lives or dies.

Bald-headed, stooped, with admitted prostate ailments, James Holiday, 73, wore grandfatherly glasses and testified about doing stabbings in a soft voice. He admitted being a founding member of the Black Guerilla Family, one of California’s four most-violent prison gangs.

He said that when ordered by a gang leader, even one who is elderly and ill, soldiers must kill when ordered. Gang members have been ordered to kill siblings. If they didn’t do it, they could be killed.

Wayne Bridgewater, 63, an Aryan Brotherhood shot-caller who killed four men in federal prisons, strode slowly, deliberately to the witness stand. His face was wrinkled but he still amply filled out a white prison T-shirt. Bridgewater gave a primer on prison etiquette, describing why Torrez asking for Rivera’s shoes on the day of the fatal beating was a deadly challenge.

“If someone did that to me, personally, I would attack him. It’s just blatant disrespect. He might as well have just walked up and slapped me,” Bridgewater testified.

He agreed with correctional officers who testified that Supermax houses dangerous gang leaders, and that many of them have gray hair.

Prosecutors used the gang etiquette against Rivera during the trial by pointing out that to sanction the hit of a Mexican Mafia leader, Richard Santiago would have needed a “green light” from two other Mexican Mafia leaders. Defense witness Daniel Vasquez, a former warden of San Quentin and an expert on the Mexican Mafia, acknowledged as much under cross-examination. Inside Supermax at the time were two leaders of the Mexican Mafia: Ruben “Nite Owl” Castro, then 45, and Adolph “Champ” Reynoso, then 61.

Vasquez testified that unless gang leaders approved the inside hit, Richard Santiago would be killed. It implied that Torrez’s death was a sanctioned hit.

Reputed Mexican Mafia assassin Arcadio Perez, 54, who is serving a life sentence for killing two other inmates, testified of his angst when Torrez ordered him to kill Rivera, his close friend and former cellmate. Perez said he told Torrez he personally liked Rivera.

” ‘If you don’t do it, it will be done to you,’ ” Torrez threatened, according to Perez.

Political dynamic shiftThe only explanation Torrez gave Perez for killing Rivera was that “Rivera had been disrespectful.”

Rivera later testified that when he entered the yard that day at 7:40 a.m., he approached Perez to give his former cellmate a hug, their normal practice, but Perez reached for his hand instead. It seemed very odd and unsettling.

“He wouldn’t look me in the eyes,” Rivera said.

Answering a question from a prosecutor, Perez testified that he never even considered warning his friend about his impending death.

“No, because if I say something, the person who is going to be killed is me,” Perez testified.

Trial testimony brought the Mexican Mafia into sharp focus.

California gang expert Richard Valdemar testified that the Mexican Mafia was a powerful prison gang formed as a syndicate in the style of the Italian Mafia. They keep their numbers tight, only 200 or 300, compared to the 54,000 members of the Sureños.

“Basically it’s a gang of old men,” Valdemar said. “It’s like ‘The Godfather’ — you don’t actually have to get your hands dirty.”

A simple nod in a prison yard can be a signal to kill, he testified.

Rivera testified that he thought his life was over when he saw Torrez, who ordered numerous prison hits, screaming and ranting that he ran the exercise yard shortly after threatening to kill him.

Rivera, then 47, explained that in a one-on-one fight the older man posed no physical danger. But that wasn’t the point: If he attacked Torrez, he knew that several Mexican Mafia members in the yard and even his friend Perez would kill him.

“Those were Tati’s soldiers … I’m not supposed to put my hands on anyone from that gang. I should have been dead that day. It happens that fast,” Rivera testified.

Santiago, a Mexican Mafia member, unexpectedly saved Rivera’s life when he tried to talk Torrez into backing down. That only made Torrez angrier.

Santiago’s sudden involvement flipped the political dynamics of the prison yard, sparing Rivera’s life and telegraphing to Perez that he didn’t have to kill his friend after all. This was now a battle between equals, one Mexican Mafia member against another. Rivera joined the battle on Santiago’s side, not fearing retaliation after Santiago took the lead.

Santiago, who was videotaped kicking a motionless Torrez in the head eight times, faces a possible death sentence in a later trial.

After Rivera’s trial, jurors told his attorney, David Lane, that they believed virtually everything Rivera had said: That Torrez had threatened his life and Perez and other inmates were ready to kill him.

What they didn’t agree with was Rivera’s explanation of needing to join Santiago in the beating by throwing three punches and kicking Torrez in the legs until he fell.

“I had to stop that threat,” Rivera had testified. “It was a threat on my life.”

At that point, his self-defense argument faltered in the eyes of jurors, Lane said in an interview: “They said, ‘Why not just let Santiago do it.’ “

Kirk Mitchell: 303-954-1206 or twitter.com/kirkmitchell