A Richmond man accused of intentionally setting fire to his family’s house and killing four family members appeared in court Tuesday to formally enter a plea to multiple murder charges. Sergio Rivera-Vega faces four counts of murder, along with arson charges and enhancements, for the August fir e that killed his father, his sister Maria, and Maria’s two young children. During a brief arraignment at the Richmond courthouse, Rivera-Vega’s public defender entered a plea of not guilty to all charges. Legal expert Steven Clark said Rivera-Vega’s mental health will likely serve as a key issue for the defense strategy moving forward. “I think you will see the defense request a psychiatrist be appointed to evaluate him and give feedback on his current status and what was his status at the time of the commission of these crimes,” Clark said. Court records detail years of alleged threats, prior restraining orders and mental health concerns leading up to the fatal blaze. In 2021, Maria told authorities her brother was using drugs and had threatened to burn the house down with the family inside. She later told authorities that Rivera-Vega had been diagnosed with schizophrenia. Clark noted that a potential insanity plea will take time to develop. “It’s a fluid decision on an insanity plea and that could take months,” Clark said. “It will certainly happen before a trial is scheduled and a big fight in this case could be whether or not he meets the level of insanity for purposes of criminal law.” Clark added that Rivera-Vega’s current mental state will also be critical in determining whether he is fit to face the charges. “The mental health question of his competency is still on the table,” Clark said. “If he is not able to assist his defense and he doesn’t understand these proceedings, we could see this go into a whole different court area.” A judge scheduled a preliminary hearing for next month in Richmond, where the crimes took place. However, the defense challenged the location, leading the judge to change the venue to Martinez. “The defense wants this case out of Richmond because of the emotional impact this case has had on that community,” Clark said. “So the case will now be moved to a different jurisdiction within Contra Costa County. That was an important strategic issue for the defense today.” Rivera-Vega is expected back in court in October, when a Martinez-based judge will hear the case. ...read more read less