Esteban Nunez was charged with murder and other counts stemming from the Oct. 4, 2008, stabbing death of Luis Santos, 22.
Fabian Nunez's son admits his role in the killing of a college student in 2008.
The former Assembly speaker's son, Esteban Nunez, had faced charges of murder, assault, vandalism, conspiracy to commit an assault and conspiracy to destroy evidence in connection to the slaying of Mesa College student Luis Santos, 22.
But on Wednesday, Esteban Nunez and another defendant, Ryan Jett, pleaded guilty to voluntary manslaughter. Both could both be sentenced to up to 16 years in prison for their roles in the killing, which took place outside a fraternity party in October 2008. If they had not taken the plea deal on Wednesday, they could have been sentenced to 25 to life if found guilty of all the charges.
Investigators said shortly after the killing that the defendants jumped a group of local college students in front of SDSU's Peterson Gym and that three victims were stabbed.
Two other men -- Rafael Garcia, 20, and Leshanor Thomas, 21 -- also pleaded guilty in connection to the incident. Garcia, who was cooperating with prosecutors, admitted taking part in a conspiracy to destroy evidence, and Thomas pleaded guilty to conspiracy to commit an assault and assault with a deadly weapon.
At a preliminary hearing last year, witness John Murray said Esteban Nunez told him, "I stabbed someone, and Jett stabbed someone, too."
Murray also said three of the defendants were drunk that night and that Jett had removed most of his clothes after returning from the fatal altercation and was soaking them in a kitchen sink. Nunez allegedly told him later that he had stabbed someone on the shoulder during the fight to help protect Garcia.
One of the defendants said, "Let's show them how we do it in Sac-town," said prosecutor Jill DeCarlo at the preliminary hearing. "The defendants were looking for trouble and they bragged that they were all carrying knives."
A witness told police how furious Esteban Nunez and his friends were about getting kicked out of a fraternity party and how they vowed revenge. Another said Nunez declared that he "got one of them" as they left a group of men, including one who said he had just been stabbed.
All four defendants were arrested in Sacramento County in December 2008 and driven to San Diego in four separate vehicles.
Esteban Nunez and Jett will be sentenced June 25.