A jury convicted Sysillia Kianna Morrison Montes De Oca in the 2022 Laguna Beach crash that killed 60-year-old Stanley Isaacs of Costa Mesa. The verdicts included gross vehicular manslaughter, hit and run with permanent and serious injury, and failing to stop at a hit and run involving injury or death, according to the Los Angeles Times. Jurors also upheld an enhancement for fleeing the scene of a vehicular manslaughter. Morrison Montes De Oca is scheduled to be sentenced.
Crash and arrest
Police said Morrison Montes De Oca struck Stanley and Catherina Isaacs shortly before 9:40 p.m. on Aug. 11, 2022, while they were crossing South Coast Highway at Pearl Street. The couple, both Costa Mesa residents, were in a marked, illuminated crosswalk; Stanley died at a hospital, and Catherina was treated for minor injuries, according to the Laguna Beach Police Department. Police identified speed as a possible contributing factor and said the posted speed limit was 35 mph.
Morrison Montes De Oca surrendered to Laguna Beach police at about 6 p.m. the following day and was booked on suspicion of vehicular manslaughter with gross negligence and felony hit and run, police said. She later posted the statutory $100,000 bail. Before the surrender, detectives located a silver 2009 Volkswagen Jetta concealed in a garage in Aliso Viejo and impounded it as evidence, according to the police release.
Arguments at trial
Deputy District Attorney Justin Kim argued that Morrison Montes De Oca was speeding, had smoked marijuana that evening and told the three other passengers she intended to accelerate before the collision. He also argued that her conduct after the crash, including returning to the area with a friend, supported the prosecution's case, according to the Los Angeles Times.
Defense attorney Mike Molfetta disputed the prosecution's account. He argued that the evidence did not establish Morrison Montes De Oca was smoking marijuana in the car, that the speed evidence was only an estimate, and that the circumstances did not support a finding of gross negligence. He also argued that she left after pressure from the other passengers and was catatonic afterward, according to the Los Angeles Times.
Coast Highway safety context
South Coast Highway is part of the state highway system. According to Caltrans District 12's 2022 Active Transportation Plan, more than 3,500 crashes involving pedestrians or bicyclists occurred on roads in the district between 2015 and 2019, killing 208 people and severely injuring 442. A separate Caltrans technical report documents a pedestrian-signal study at Coast Highway, or State Route 1, and Broadway Street in Laguna Beach. The report says the signal at that intersection was operated and maintained by Caltrans District 12.
Related case
Jack Francis Bannigan, whom prosecutors linked to the concealment of the damaged vehicle, pleaded guilty July 9, 2026, to being an accessory after the fact. He received one year of informal probation and was ordered to complete 120 hours of community service, according to the Los Angeles Times.
