Amador Pacheco was being so badly beaten by a group of men who attacked him at Santa Rosa's Youth Community Park that his 14-year-old daughter stepped in to try to protect him, a prosecutor said Tuesday.

As Pacheco, 40, slumped to the ground under a withering barrage of kicks and punches, the girl went to the ground too, covering his head with her own body, absorbing blows herself, Deputy District Attorney Jason Riehl said.

"Because she thought he was going to die," Riehl said.

But Pacheco survived. The prosecutor said the beating ended when another Pacheco family member yelled out that she was calling 911. Police arrived to find people running away in different directions and Pacheco lying on his back, slipping in and out of consciousness and covered in blood, officers said.

Doctors at Santa Rosa Memorial Hospital treated him for a broken nose along with welts and abrasions covering his head and body.

His story emerged in the opening day of trial for five men accused of taking part in the June 2012 assault at a low-rider show.

Police initially charged 11 suspects with Pacheco's beating but resolved six of the cases with jail sentences or dismissals.

The remaining defendants have pleaded not guilty and are going to trial. They are Anthony Cervantes, 25, Robert Sandoval, 36, and Juan Tovar, 20, all of Santa Rosa; Robert Flett, 27, of Rohnert Park and Carl Hastie, 27, of Marin County.

In addition to assault charges, prosecutors allege all but Sandoval acted for the benefit of or in association with a criminal gang.

The trial is expected to run for four weeks.

At a preliminary hearing last year, Pacheco's wife, Raquel Pacheco, testified that she was hosting a birthday party alongside the car show that featured rappers and a beer drinking contest when Hastie punched her 18-year-old daughter, Icelya.

Icelya Pacheco had apparently confronted Cervantes, who called Amador Pacheco a snitch, witnesses said.

The husband jumped to her defense and was attacked by as many as 10 men, she testified.

At one point, Flett, who was hired as a rapper for the car show, walked up and smashed a bottle over his head, she said.

Raquel Pacheco recalled seeing her husband's face as he was being pummeled and realizing "he was done."

Prosecutors tried to buttress their gang allegations by showing gang tattoos on four of the men. They displayed bare-chested photos to the jury showing various inked inscriptions, proclaiming allegiance with the norteno gang.

But in their opening statements Tuesday, defense lawyers challenged the gang claims, saying the dispute was motivated by a personal or family dispute between Pacheco and Cervantes.

And two of the defendants, Cervantes and Tovar, claimed they were not present during the altercation.