Edwin Ramos, 25 was found guilty on three counts of first-degree murder in the June 22, 2008, shooting deaths of Tony Bologna, 48, and two of his sons, Michael, 20, and Matthew, 16, the San Francisco Chronicle reported. Ramos also was found guilty of attempted murder and related firearms and gang enhancements.
The jury, which heard three months of testimony and had been deliberating since May 2, could not reach a decision on two other counts.
Ramos, a suspected illegal immigrant from El Salvador, is to be sentenced June 4. He could be sentenced to life in prison without parole.
The newspaper said Ramos cried upon hearing the verdicts, as did Danielle Bologna, Tony Bologna's wife, who was heard to say "Yes, yes, God."
Another son, Andrew, now 21, was the only one to survive the attack, which occurred while the father was driving his sons home from a family gathering in Fairfield.
Authorities said Ramos mistook at least one of the young Bolognas for a Mission District gang rival and fired at them from another car.