S.F. judge denies reducing charges against woman in fatal West Portal crash

Mary Fong Lau, 80, faces four felony counts of gross vehicular manslaughter for the 2024 incident that killed a family of four.

Jan. 30, 2026 at 7:23pm by Ben Kaplan

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A San Francisco Superior Court judge ruled that Mary Fong Lau, 80, will face four felony counts of gross vehicular manslaughter for a 2024 crash that killed a family of four in the city's West Portal neighborhood. Lau's attorney had sought to reduce the charges, but the judge denied the motion, saying prosecutors have a strong case against Lau despite her claims of a vehicle malfunction.

Why it matters

The case has drawn significant attention in San Francisco due to the tragic loss of life and the questions it raises about elderly drivers, vehicle safety, and the judicial system's handling of such incidents. The ruling also sets the stage for a high-profile criminal trial and a parallel civil lawsuit filed by the victims' families.

The details

On March 16, 2024, Lau's Mercedes SUV slammed into a West Portal bus shelter at over 70 mph, killing Diego Cardoso de Oliveira, 40, his 1-year-old son Joaquim, and Matilde Moncada Ramos Pinto, 38, and her 3-month-old son Cauê. Lau initially told investigators she accidentally hit the gas instead of the brake while trying to park, but later claimed her vehicle had a malfunction. Prosecutors say there's no evidence of a malfunction, and that video footage shows Lau did not appear to be braking.

  • The crash occurred on March 16, 2024.
  • In July 2024, Lau pleaded not guilty to the felony charges.
  • In July 2024, the surviving family members filed a wrongful death civil suit against Lau.
  • In May 2025, the family filed a new civil suit alleging Lau transferred assets to make her estate less valuable.

The players

Mary Fong Lau

An 80-year-old woman accused of killing a family of four after her Mercedes SUV slammed into a West Portal bus shelter at over 70 mph in 2024.

Diego Cardoso de Oliveira

A 40-year-old man who was killed in the 2024 crash along with his 1-year-old son.

Matilde Moncada Ramos Pinto

A 38-year-old woman who was killed in the 2024 crash along with her 3-month-old son.

Seth Morris

The attorney representing Mary Fong Lau, who argued the charges against her should be reduced.

James Quadra

One of the attorneys representing the victims' families in their civil lawsuits against Lau.

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What they’re saying

“Something happened in the street that at this point, is unexplained. What's hard about this case is that sometimes things are unexplained and tragic.”

— Seth Morris, Attorney for Mary Fong Lau (San Francisco Chronicle)

“In conversations, I know she understands the depth of loss.”

— Seth Morris, Attorney for Mary Fong Lau (San Francisco Chronicle)

What’s next

The criminal trial against Mary Fong Lau is expected to begin in the coming months, and the civil lawsuits filed by the victims' families are also ongoing.

The takeaway

This tragic case highlights the complex issues surrounding elderly drivers, vehicle safety, and the legal system's handling of such incidents. It has devastated a family and a community, and will likely prompt further scrutiny of policies and procedures around licensing, vehicle inspections, and prosecuting vehicular manslaughter charges.