An attorney for a 17-year-old youth charged with capital murder admitted Monday that his client stabbed a Salt Lake man, but he said Fred Alvarez did not stab and kill the man's son.

During the trial's first day of testimony, witnesses re-created the bloody fight that occurred on June 9 in which a father and his son were stabbed to death after they tried to gain entrance into a drinking party in Rose Park."We did not kill Shane Newingham. That's our opinion and we're going to stick to it," attorney Robert Van Sciver told the seven-man, five-woman jury.

He said Don Newingham, the father, taunted the assailants and would not back down when asked to leave the party. He said Shane was the catalyst that changed the incident "from cuss words to carnage."

Should the jury find Alvarez guilty of killing Don Newingham but not his son, Shane Newingham, Van Sciver said, he should be charged at most with the lesser crime of second-degree murder.

Alvarez is charged with two counts of first-degree murder and, if he is convicted, prosecutors will likely seek the death penalty.

Deputy Salt Lake County Attorney Kent Morgan said the fight was motivated by nothing more than pride. He said Alvarez and "a mob" of others attacked and killed the Newinghams like a "swarm of piranhas going after beef."

He said Alvarez stabbed Don Newingham four times in the back with the knife going in all the way to the hilt. He said Alvarez even pulled the knife out and reinserted it into the same wound.

"Then, as Don Newingham was dying, they descended on Shane," he said.

Richard Gabaldon - once charged with capital murder in the case - testified that Don Newingham and Kelly Salas approached his house at 467 N. Morton Drive about midnight and asked if they could come in and party. After he told them "no" several times, he said, Alvarez pulled out a large knife.

"He said you'd better leave or this is the knife I'm going to use," Gabaldon testified.

Don Newingham and Salas returned to the car before "Freddy started taking off across the yard." Gabaldon, 20, then followed him outside.

"(Don) said, `I'm not going to let no young punk pull a knife on me. I'm going to stick him first,' " Gabaldon said, adding that he grabbed the 39-year-old father and then the melee began.

"I heard somebody yell, `Get off my dad!' " and then he said he began fighting with 18-year-old Shane.

After more fighting, Gabaldon said he remembers Don Newingham lying face-up on the ground. "I went back and saw someone laying there . . . I stomped on his head and I was kicking him."

He said he kicked Don Newingham three times and also kicked Salas before his sister yelled at him to stop. "She said, `Leave him alone, you're killing them.' I said `No I'm not. These guys just got knocked out.' "

Gabaldon said he saw Alvarez limp away from the fight but did not see if either Newingham was still alive after that. He said he later heard Anthony DeHerrera say "I got one of them; I got them in the back of the neck."

DeHerrera, 19, was originally booked into jail in connection with the incident, but he was later released.

When asked if he intended to hurt the victims, Gabaldon said, "Yes."

"I knew what I was doing, but I was out of control."

Prosecutors offered to let Gabaldon plead guilty to two counts of aggravated assault - greatly reduced from original capital homicide charges - in exchange for his truthful testimony against Alvarez. But his testimony seemed to provide little, if any, hard evidence against Alvarez.