Authorities said Esteban Nunez and his friends were mad after being turned away from a party last October. He and his friends got into an argument with 22-year-old Luis Santos, who was a college student at San Diego Mesa College, and his friends.
Santos was stabbed to death and died at the scene.
Fabian Nunez said in a statement: "This is a very difficult and painful experience for every family involved. Maria and I love our children very much. We are confident our son Esteban will be cleared of the charges he is facing. We will continue to fully cooperate with all law enforcement officials and have faith in our system of justice."
Esteban Nunez and friends Ryan Jett, Leshanor Thomas and Rafael Garcia, who are also 19, face one count of murder and three counts of assault with a deadly weapon.
Esteban Nunez and at least one of the other suspects are college students in the Sacramento area, and had gone to San Diego "to visit friends and party," police said. A female witness came forward after the fight and provided information that helped police trace the suspects.
Fabian Nunez, 41, was elected to the Assembly in 2002 and became speaker in 2004.
The victim's mother said she worries that the former speaker's political clout could influence the judicial process.
"I hope that it's not because people have clout that are going to walk away. If these people did the crime, then they need to be punished and do their time," said the victim's mother Kathy Santos.
Fabian Nunez now works for a New York-based consulting firm.
He recently stepped down from his post as speaker after a failed attempt to change California's term-limit laws.
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