The trial is being held in a secured courtroom with extraordinary security. The courtroom floor is shielded from the public by a bulletproof window.
Among the curious spectators were friends and family of the victims.
Tony Bologna's widow Danielle was led into court through a back door. Her sole surviving son Andrew is the prosecution's main witness. Authorities are concerned they could be the target of retaliation from the violent Latin American gang MS-13, of which Edwin Ramos is reportedly a member.
District Attorney George Gascon came to court to show his support for the Bologna family.
"We have an entire family, we have a mother, we have a lot of kids that have been impacted by this case very, very tragically," Gascon said.
Prosecutor Harry Dorfman led the jurors through the chronology of that fatal day, June 22, 2008. Ramos is accused to shooting to death Bologna and two of his three sons as he drove next to their car on a narrow street in the Excelsior District. Dorfman says Ramos wanted to avenge the shooting of a fellow gang member days before by their rivals, the Nortenos, and that he mistook the Bolognas as members of the gang.
Dorfman said "Andrew saw Ramos produce a 9mm handgun and saw Ramos shoot his father and brothers...Andrew ducked down when the shooting started. That saved his life."
Ramos was arrested after Andrew Bologna identified him in a photo lineup.
In the police interview, Ramos first denied involvement, saying, "No way dude, I wasn't there...I have no idea what happened."
Later, Ramos admitted driving the car but said a passenger was the shooter. Ramos said, "He stuck it out of the window...pointed it all the way out" and fired the fatal shots.
Defense attorney Marla Zamora explains why Ramos changed his story.
"Would you want to take the rap for this horrible crime that you didn't do? That you didn't know it was going to occur even and be left holding the bag?" Zamora said.
The gang member Ramos blames for the murders has disappeared.
Jurors were told the trial could last a long time, perhaps half a year, there are more than 20,000 pages of discovery and potentially more than 100 witnesses.